New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels PRELIMINARIES Stability of Time Delay Systems Delay-Independent Stability : If a time-delay system is asymptotically stable for any delay values belonging to R + , the system is said to be delay-independent asymptotically stable. Delay-Dependent Stability : If a time-delay system is asymptotically stable for all delay values belonging to a compact subset D of R + , the system is said to be delay-dependent asymptotically stable. Rate-Independent Stability : For a delay-dependent asymptotically stable time delay system, if the stability does not depend on the variation rate of delays or on the time derivative of delays, the system is said to be rate-independent asymptotically stable. Rate-Dependent Stability : For a delay-dependent asymptotically stable time delay system, if the stability depends on the variation rate of delays or on the time derivative of delays, the system is said to be rate-dependent asymptotically stable. 18 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels PRELIMINARIES Stability of Time Delay Systems Delay-Independent Stability : If a time-delay system is asymptotically stable for any delay values belonging to R + , the system is said to be delay-independent asymptotically stable. Delay-Dependent Stability : If a time-delay system is asymptotically stable for all delay values belonging to a compact subset D of R + , the system is said to be delay-dependent asymptotically stable. Rate-Independent Stability : For a delay-dependent asymptotically stable time delay system, if the stability does not depend on the variation rate of delays or on the time derivative of delays, the system is said to be rate-independent asymptotically stable. Rate-Dependent Stability : For a delay-dependent asymptotically stable time delay system, if the stability depends on the variation rate of delays or on the time derivative of delays, the system is said to be rate-dependent asymptotically stable. 18 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels PRELIMINARIES Stability of Time Delay Systems General System with Piecewise Time-Varying Delays : x ( t ) = f ( x ( t ) , x ( t − τ 1 ( t )) , u ( t ) , u ( t − τ 2 ( t ))) , ˙ x ( t 0 + θ ) = ˙ x ( t 0 + θ ) = φ ( θ ) , ˙ φ ( θ ) , (3) u ( t 0 + θ ) = ζ ( θ ) , θ ∈ [ − h, 0] . Linear Case : � x ( t ) = A 0 x ( t ) + � n i =1 A i x ( t − τ 1 i ( t )) + B 0 u ( t ) + � m ˙ j =1 B j u ( t − τ 2 j ( t )) , x ( t 0 + θ ) = ˙ x ( t 0 + θ ) = φ ( θ ) , ˙ φ ( θ ) , θ ∈ [ − h, 0] . (4) 19 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels PRELIMINARIES Stability of Time Delay Systems Lyapunov-Krasovskii Functionals (LKF) - Linear Case : � Search of suitable V ( x ( t ) , ˙ x ( t )) [E. Fridman, IMA Journal of Mathematical Control and Information, 2006] : � t � t x ( t )) = x ( t ) T Px ( t ) + x ( s ) T S a x ( s ) ds + x ( s ) T Sx ( s ) ds V ( x ( t ) , ˙ t − h 2 t − h 1 � 0 � t x ( s ) T R ˙ + h 1 ˙ x ( s ) dsdθ − h 1 t + θ � − h 1 � t q � x ( s ) T R ai ˙ + ( h 2 − h 1 ) ˙ x ( s ) dsdθ. − h 2 t + θ i =1 (5) � Asymptotical stability condition depending of the derivative of V ( x ( t ) , ˙ x ( t )) along the system trajectories : ˙ V ( x ( t ) , ˙ x ( t )) > 0 , V ( x ( t ) , ˙ x ( t )) < 0 , for any x t � = 0 , (6) ˙ and V ( x (0) , ˙ x (0)) = 0 , V ( x (0) , ˙ x (0)) = 0 . 20 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES System Description & Assumptions 2. Novel Control Schemes � System Description & Assumptions; � Robust Stability Conditions; � Control Scheme 1 - Bilateral State Feedback Control Scheme [B. Zhang et al., CCDC, 2011] ; � Control Scheme 2 - Force-Reflecting Control Scheme ; � Control Scheme 3 - Force-Reflecting Proxy Control Scheme [B. Zhang et al., ETFA, 2011] ; � Results and Analysis ; 21 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES System Description & Assumptions General Teleoperation Structure : Our Master/Slave Controller Solution : � Lyapunov-Krasovskii functional (LKF) ; � H ∞ control ; � Linear Matrix Inequality (LMI) optimization; 22 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES System Description & Assumptions General Teleoperation Structure : From Property 1 - Assumption 1 : Linear master/slave systems = ⇒ x m ( t ) = ( A m − B m K m ˙ 0 ) x m ( t ) + B m ( F m ( t ) + F h ( t )) , (7) x s ( t ) = ( A s − B s K s ˙ 0 ) x s ( t ) + B s ( F s ( t ) + F e ( t )) , θ s ( t ) ∈ R n ; K m x m ( t ) = ˙ θ m ( t ) ∈ R n , x s ( t ) = ˙ 0 & K s 0 : supposed to be known; 23 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES System Description & Assumptions General Teleoperation Structure : From Property 2 - Assumption 2 : Internet/Ethernet/Wifi... = ⇒ τ 1 ( t ) , τ 2 ( t ) ∈ [ h 1 , h 2 ] , h 1 ≥ 0 ; 24 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES System Description & Assumptions General Teleoperation Structure : From Property 3 - Assumption 3 : Time-stamped data packets = ⇒ ˆ τ 1 ( t ) = τ 1 ( t ) , ˆ τ 2 ( t ) = τ 2 ( t ) ; 25 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions 2. Novel Control Schemes � System Description & Assumptions; � Robust Stability Conditions; � Control Scheme 1 - Bilateral State Feedback Control Scheme ; [B. Zhang et al., CCDC, 2011] ; � Control Scheme 2 - Force-Reflecting Control Scheme ; � Control Scheme 3 - Force-Reflecting Proxy Control Scheme [B. Zhang et al., ETFA, 2011] ; � Results and Analysis ; 26 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions Linear Time Delay System : � x ( t ) = A 0 x ( t ) + � q ˙ i =1 A i x ( t − τ i ( t )) , (8) x ( t 0 + θ ) = ˙ x ( t 0 + θ ) = φ ( θ ) , ˙ φ ( θ ) , θ ∈ [ − h 2 , 0] . Asymptotical Stability Theorem [E. Fridman, IMA Journal of Mathematical Control and Information, 2006] : � P > 0 , R > 0 , S > 0 , S a > 0 , R ai > 0 , and P 2 , P 3 , Y 1 , Y 2 , i = 1 , 2 , ..., q ; � LMI condition is feasible ; � Rate-independent asymptotically stable for time-varying delays τ i ( t ) ∈ [ h 1 , h 2 ] , i = 1 , 2 , ..., q ; 27 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions Asymptotical Stability Theorem : 12 R + � q Γ1 11 Γ1 i =1 P T 2 Ai − qY T qY T − P T 2 A 1+ Y T ... − P T 2 Aq + Y T Y T Y T ... 1 1 1 1 1 1 � q Γ1 i =1 P T 3 Ai − qY T qY T − P T 3 A 1+ Y T ... − P T 3 Aq + Y T Y T Y T � ... 22 2 2 2 2 2 2 − S − R 0 0 0 0 0 0 0 � � − Sa 0 0 0 0 0 0 � � � Γ 1 = − Ra 1 0 0 0 0 0 < 0 , � � � � � � � � � ... 0 0 0 0 − Raq 0 0 0 � � � � � � � � � � � � � − Ra 1 0 0 0 � � � � � � � � ... � − Raq � � � � � � � � (9) Γ 1 11 = S + S a − R + A T 0 P 2 + P T Γ 1 12 = P − P T 2 + A T 2 A 0 , 0 P 3 , q � (10) Γ 1 22 = − P 3 − P T 3 + h 2 1 R + ( h 2 − h 1 ) 2 R ai . i =1 28 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions H ∞ Performance - Delay-Free with Perturbation : � x ( t ) ˙ = Ax ( t ) + Bw ( t ) , (11) z ( t ) = Cx ( t ) . � ∞ ( z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t )) dt < 0 , J ( w ) = 0 (12) ( sup w ( � z ( t ) � 2 ) < γ ) . � w ( t ) � 2 V ( x ( t )) + z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t ) < 0 , V ( x ( t )) = x ( t ) T Px ( t ) . ˙ Robust Stability Theorem : � P > 0 , P 2 , P 3 , and a positive scalar γ > 0 ; � LMI condition is feasible (see manuscript) ; � Asymptotically stable with H ∞ performance J ( w ) < 0 ; 29 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions H ∞ Performance - Delay-Free with Perturbation : � x ( t ) ˙ = Ax ( t ) + Bw ( t ) , (11) z ( t ) = Cx ( t ) . � ∞ ( z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t )) dt < 0 , J ( w ) = 0 (12) ( sup w ( � z ( t ) � 2 ) < γ ) . � w ( t ) � 2 V ( x ( t )) + z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t ) < 0 , V ( x ( t )) = x ( t ) T Px ( t ) . ˙ Robust Stability Theorem : � P > 0 , P 2 , P 3 , and a positive scalar γ > 0 ; � LMI condition is feasible (see manuscript) ; � Asymptotically stable with H ∞ performance J ( w ) < 0 ; 29 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions H ∞ Performance - Delay-Free with Perturbation : � x ( t ) ˙ = Ax ( t ) + Bw ( t ) , (11) z ( t ) = Cx ( t ) . � ∞ ( z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t )) dt < 0 , J ( w ) = 0 (12) ( sup w ( � z ( t ) � 2 ) < γ ) . � w ( t ) � 2 V ( x ( t )) + z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t ) < 0 , V ( x ( t )) = x ( t ) T Px ( t ) . ˙ Robust Stability Theorem : � P > 0 , P 2 , P 3 , and a positive scalar γ > 0 ; � LMI condition is feasible (see manuscript) ; � Asymptotically stable with H ∞ performance J ( w ) < 0 ; 29 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions Robust Stability Condition - Teleoperation Case : � LKF asymptotical stability condition with several time-varying delays + � H ∞ performance improvement condition without time-varying delays but with the perturbation = � Robust stability condition with several time-varying delays and the perturbation : x ( t ) = A 0 x ( t ) + � q ˙ i =1 A i x ( t − τ i ( t )) + Bw ( t ) , z ( t ) = Cx ( t ) , (13) x ( t 0 + θ ) = ˙ x ( t 0 + θ ) = φ ( θ ) , ˙ φ ( θ ) , θ ∈ [ − h 2 , 0] , x ( t )) + z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t ) < 0 . ˙ V ( x ( t ) , ˙ 30 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions Robust Stability Condition - Teleoperation Case : � LKF asymptotical stability condition with several time-varying delays + � H ∞ performance improvement condition without time-varying delays but with the perturbation = � Robust stability condition with several time-varying delays and the perturbation : x ( t ) = A 0 x ( t ) + � q ˙ i =1 A i x ( t − τ i ( t )) + Bw ( t ) , z ( t ) = Cx ( t ) , (13) x ( t 0 + θ ) = ˙ x ( t 0 + θ ) = φ ( θ ) , ˙ φ ( θ ) , θ ∈ [ − h 2 , 0] , x ( t )) + z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t ) < 0 . ˙ V ( x ( t ) , ˙ 30 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Robust Stability Conditions Robust Stability Condition - Teleoperation Case : � LKF asymptotical stability condition with several time-varying delays + � H ∞ performance improvement condition without time-varying delays but with the perturbation = � Robust stability condition with several time-varying delays and the perturbation : x ( t ) = A 0 x ( t ) + � q ˙ i =1 A i x ( t − τ i ( t )) + Bw ( t ) , z ( t ) = Cx ( t ) , (13) x ( t 0 + θ ) = ˙ x ( t 0 + θ ) = φ ( θ ) , ˙ φ ( θ ) , θ ∈ [ − h 2 , 0] , x ( t )) + z ( t ) T z ( t ) − γ 2 w ( t ) T w ( t ) < 0 . ˙ V ( x ( t ) , ˙ 30 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 1 - Bilateral State Feedback Control Scheme 2. Novel Control Schemes � System Description & Assumptions; � Robust Stability Conditions; � Control Scheme 1 - Bilateral State Feedback Control Scheme ; [B. Zhang et al., CCDC, 2011] ; � Control Scheme 2 - Force-Reflecting Control Scheme ; � Control Scheme 3 - Force-Reflecting Proxy Control Scheme [B. Zhang et al., ETFA, 2011] ; � Results and Analysis ; 31 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 1 - Bilateral State Feedback Control Scheme Control Scheme 1 - Bilateral State Feedback Control Scheme : � Delayed state feedback C 1 & C 2 : 1 ˙ 1 ˙ F s ( t ) = − K 1 τ 1 ( t )) − K 2 C 1 : θ s ( t − ˆ θ m ( t − τ 1 ( t )) − K 3 1 ( θ s ( t − ˆ τ 1 ( t ) − θ m ( t − τ 1 ( t ))) , (14) 2 ˙ 2 ˙ F m ( t ) = − K 1 θ s ( t − τ 2 ( t )) − K 2 C 2 : θ m ( t − ˆ τ 2 ( t )) − K 3 2 ( θ s ( t − τ 2 ( t ) − θ m ( t − ˆ τ 2 ( t ))) . � ˆ τ 1 ( t ) = τ 1 ( t ) and ˆ τ 2 ( t ) = τ 2 ( t ) from Assumption 3 ; 32 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 1 - Bilateral State Feedback Control Scheme Control Scheme 1 - Master/Slave Controller Design : x ms ( t ) ˙ = ( A ms − B ms K 0 ) x ms ( t ) + B ms u ms ( t ) + B ms w ms ( t ) , = − K 1 ms x ms ( t − τ 1 ( t )) − K 2 u ms ( t ) ms x ms ( t − τ 2 ( t )) , z ms ( t ) = C ms x ms ( t ) , (15) � � ˙ θs ( t ) � Fs ( t ) � � Fe ( t ) � x ms ( t ) = ˙ , u ms ( t ) = , w ms ( t ) = , θm ( t ) Fh ( t ) Fm ( t ) θs ( t ) − θm ( t ) (16) � � z ms ( t ) = , θs ( t ) − θm ( t ) � As � � Bs � � � 0 0 0 B 1 ms B 2 A ms = 0 Am 0 , B ms = = , 0 Bm ms 1 − 1 0 0 0 � � � � � � Ks 0 0 K 1 1 K 2 1 K 3 0 0 0 K 1 K 2 (17) 0 K 0 = ms = ms = , 1 , K 1 2 K 2 2 K 3 , Km 0 0 0 0 0 0 2 � � C ms = 0 0 1 . 33 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 1 - Bilateral State Feedback Control Scheme Control Scheme 1 - Master/Slave Controller Design : � Transformation so to apply robust control condition : = A 0 ms x ms ( t ) + A 1 ms x ms ( t − τ 1 ( t )) + A 2 x ms ( t ) ˙ ms x ms ( t − τ 2 ( t )) + B ms w ms ( t ) , z ms ( t ) = C ms x ms ( t ) , (18) A 0 ms = A ms − B ms K 0 , A 1 ms = − B ms K 1 ms = − B 1 A 2 ms = − B ms K 2 ms = − B 2 ms K 1 , ms K 2 , (19) � � � � K 1 K 2 K 3 K 1 K 2 K 3 K 1 = , K 2 = . (20) 1 1 1 2 2 2 34 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 1 - Bilateral State Feedback Control Scheme Control Scheme 1 - Control Objectives : � LKF : the system stability under the time-varying delays τ 1 ( t ) , τ 2 ( t ) ∈ [ h 1 , h 2 ] ; � H ∞ control : the impact γ of disturbances w ms ( t ) on z ms ( t ) ( θ s ( t ) − θ m ( t ) ) ; Control Scheme 1 - Master/Slave Controller Design Theorem : � P > 0 , R > 0 , S > 0 , S a > 0 , R a 1 > 0 , R a 2 > 0 , P 2 , W 1 , W 2 , Y 1 , Y 2 , and positive scalars γ and ξ ; � LMI condition is feasible (see manuscript) ; � Rate-independent asymptotically stable with H ∞ performance J ( w ) < 0 for time-varying delays τ 1 ( t ) , τ 2 ( t ) ∈ [ h 1 , h 2 ] : K 1 = W 1 P − 1 K 2 = W 2 P − 1 , . (21) 2 2 35 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 2 - Force-Reflecting Control Scheme 2. Novel Control Schemes � System Description & Assumptions; � Robust Stability Conditions; � Control Scheme 1 - Bilateral State Feedback Control Scheme [B. Zhang et al., CCDC, 2011] ; � Control Scheme 2 - Force-Reflecting Control Scheme ; � Control Scheme 3 - Force-Reflecting Proxy Control Scheme [B. Zhang et al., ETFA, 2011] ; � Results and Analysis ; 36 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 2 - Force-Reflecting Control Scheme Control Scheme 2 - Force-Reflecting Control Scheme : � ˆ F e ( t ) : F m ( t ) = ˆ F e ( t − τ 2 ( t )) ; � C with controller gain K i , i = 1 , 2 , 3 : F s ( t ) = − K 1 ˙ τ 1 ( t )) − K 2 ˙ C : θ s ( t − ˆ θ m ( t − τ 1 ( t )) (22) − K 3 ( θ s ( t − ˆ τ 1 ( t ) − θ m ( t − τ 1 ( t ))) . 37 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 2 - Force-Reflecting Control Scheme Control Scheme 2 - Slave Controller Design : � x ms ( t ) ˙ = ( A ms − B ms K 0 ) x ms ( t ) + B ms u ms ( t ) + B ms w ms ( t ) , u ms ( t ) = − K ms x ms ( t − τ 1 ( t )) , (23) � � K 1 K 2 K 3 K ms = . (24) 0 0 0 ⇓ � = A 0 ms x ms ( t ) + A 1 x ms ( t ) ˙ ms x ms ( t − τ 1 ( t )) + B ms w ms ( t ) , (25) z ms ( t ) = C ms x ms ( t ) , � � A 1 ms = − B ms K ms = − B 1 ms K, K = . (26) K 1 K 2 K 3 38 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme 2. Novel Control Schemes � System Description & Assumptions; � Robust Stability Conditions; � Control Scheme 1 - Bilateral State Feedback Control Scheme ; [B. Zhang et al., CCDC, 2011] ; � Control Scheme 2 - Force-Reflecting Control Scheme ; � Control Scheme 3 - Force-Reflecting Proxy Control Scheme [B. Zhang et al., ETFA, 2011] ; � Results and Analysis ; 39 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Force-Reflecting Proxy Control Scheme : � From master to slave : ˙ θ m ( t ) /θ m ( t ) / ˆ F h ( t ) , the position tracking ; � From slave to master : F m ( t ) = ˆ F e ( t − τ 2 ( t )) , the force tracking ; 40 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Slave Controller Description : � ’P’ : x p ( t ) = ( A m − B m K m ˙ 0 ) x p ( t ) − B m F p ( t ) (27) + B m ( ˆ τ 1 ( t )) + ˆ F e ( t − ˆ F h ( t − τ 1 ( t ))) , x p ( t ) = ˙ θ p ( t ) ∈ R n . 41 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Slave Controller Description : � � � L = = ⇒ θ p ( t ) → θ m ( t ) : L 1 L 2 L 3 � � ˙ θ p ( t − ˆ τ 1 ( t )) F p ( t ) = L . (27) ˙ θ m ( t − τ 1 ( t )) θ p ( t − ˆ τ 1 ( t )) − θ m ( t − τ 1 ( t )) 41 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Slave Controller Description : � � of the controller ¯ � K = K 1 K 2 K 3 C = ⇒ θ s ( t ) → θ p ( t ) : � � ˙ θ s ( t ) F s ( t ) = − K . (28) ˙ θ p ( t ) θ s ( t ) − θ p ( t ) 41 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Master-Proxy Synchronization : � = A 0 mp x mp ( t ) + A 1 x mp ( t ) ˙ mp x mp ( t − τ 1 ( t )) + B mp w mp ( t ) , (29) z mp ( t ) = C mp x mp ( t ) . ˙ � ˆ � θp ( t ) τ 1( t ))+ ˆ Fe ( t − ˆ Fh ( t − τ 1( t )) , x mp ( t ) = ˙ w mp ( t ) = , θm ( t ) Fm ( t )+ Fh ( t ) θp ( t ) − θm ( t ) (30) � � z mp ( t ) = . θp ( t ) − θm ( t ) 42 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Master-Proxy Synchronization : � A m − B m K m � � B m � � � 0 0 0 0 A 0 mp = , B mp = = , A m − B m K m B 1 mp B 2 0 0 0 B m 0 mp 0 0 1 − 1 0 � � C mp = , 0 0 1 � − B m L 1 − B m L 2 − B m L 3 � A 1 = − B 1 mp = mp L. 0 0 0 0 0 0 (31) 43 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Proxy-Slave Synchronization : � x ps ( t ) ˙ = A ps x ps ( t ) + B ps w ps ( t ) , (32) z ps ( t ) = C ps x ps ( t ) , ˙ θs ( t ) � � , x ps ( t ) = ˙ z ps ( t ) = θs ( t ) − θp ( t ) , θp ( t ) θs ( t ) − θp ( t ) (33) � � F e ( t ) w ps ( t ) = . ˆ τ 1 ( t )) + ˆ F e ( t − ˆ F h ( t − τ 1 ( t )) − F p ( t ) 44 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Proxy-Slave Synchronization : � Bs � � � � � 0 B 1 ps B 2 B ps = = , C ps = , 0 Bm 0 0 1 ps 0 0 � As − BsKs � 0 − BsK 1 − BsK 2 − BsK 3 A ps = Am − BmKm 0 0 0 1 − 1 0 (34) � As − BsKs � � − BsK 1 − BsK 2 − BsK 3 � 0 0 0 Am − BmKm = + 0 0 0 0 0 0 0 0 0 1 − 1 0 = ( A 0 ps − B 1 ps K ) . . 45 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Control Scheme 3 - Global Performance Analysis : � = A 0 mps x mps ( t ) + A 1 x mps ( t ) ˙ mps x mps ( t − τ 1 ( t )) + B mps w mps ( t ) , z mps ( t ) = C mps x mps ( t ) , (35) ˙ θs ( t ) � � � � ˙ θp ( t ) Fe ( t ) θs ( t ) − θp ( t ) x mps ( t ) = w mps ( t ) = ˆ τ 1( t ))+ ˆ z mps ( t ) = ˙ , Fe ( t − ˆ Fh ( t − τ 1( t )) , . θm ( t ) θp ( t ) − θm ( t ) θs ( t ) − θp ( t ) Fm ( t )+ Fh ( t ) θp ( t ) − θm ( t ) (36) As − BsKs 0 − BsK 1 − BsK 2 0 − BsK 3 0 Am − BmKm 0 0 0 0 0 A 0 mps = Am − BmKm , 0 0 0 0 0 1 − 1 0 0 0 0 1 − 1 0 0 0 0 0 0 0 Bs 0 0 � � 0 − BmL 1 − BmL 2 0 − BmL 3 0 0 Bm A 1 , 0 0 0 1 0 mps = B mps = , C mps = . 0 0 0 0 0 0 0 Bm 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (37) 46 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Control Scheme 3 - Force-Reflecting Proxy Control Scheme Conclusions : � Control Scheme 1 - Bilateral state feedback control scheme ; � Control Scheme 2 - Force-reflecting control scheme ; � Control Scheme 3 - Force-reflecting proxy control scheme ; Time Delays Control Schema Position Tracking Force Tracking Constant Time-varying √ √ √ 1 √ √ √ √ 2 √ √ √ √ 3 � Force estimation/measure : 2 & 3 ; � Better performance, but additional computation load : 3 ; 47 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis 2. Novel Control Schemes � System Description & Assumptions; � Robust Stability Conditions; � Control Scheme 1 - Bilateral State Feedback Control Scheme [ B. Zhang et al., CCDC, 2011 ]; [B. Zhang et al., CCDC, 2011] ; � Control Scheme 2 - Force-Reflecting Control Scheme ; � Control Scheme 3 - Force-Reflecting Proxy Control Scheme [B. Zhang et al., ETFA, 2011] ; � Results and Analysis ; 48 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Simulation Conditions : � Maximum amplitude of time-varying delays : 0 . 2 s ; � Master, proxy and slave models : 1 /s , 1 /s and 2 /s ; Poles : [ − 100 . 0] . K 0 m = 100 , K 0 s = 50 ; � � � K 1 = − 0 . 1870 − 0 . 0368 65 . 0846 , � � (38) γ C 1 /C 2 K 2 = 0 . 4419 0 . 0813 − 153 . 8704 , = 0 . 0123 . min � � � γ L L = − 1 . 4566 0 . 1420 282 . 482 , min = 0 . 0081 , � � (39) γ K K = − 29 . 9635 − 3 . 6393 618 . 536 , min = 0 . 0075 . Global stability of the system is verified with γ g min = 0 . 0062 ; 49 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Abrupt Tracking Motion : 50 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Abrupt Tracking Motion : 51 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Wall Contact Motion : � Hard wall : the stiffness K e = 30 kN/m , the position x = 1 . 0 m ; � Our aims : 1. When the slave robot reaches the wall, the master robot can stop as quickly as possible ; 2. When the slave robot returns after hitting the wall ( F e ( t ) = 0 ), the system must restore the position tracking between the master and the slave ; 3. When the slave contacts the wall, the force tracking from the slave to the master can be assured ; 52 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Wall Contact Motion : 53 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Wall Contact Motion : 54 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Wall Contact Motion : � Force response in wall contact motion ( F m ( t ) ; ˆ F e ( t ) ). 55 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels CONTROL SCHEMES Results and Analysis Wall Contact Motion under Large Delays h 2 = 1 . 0 s : 56 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach 3. Robustness Aspects � Discrete-Time System [B. Zhang et al., TDS, 2012] : ◮ Discrete-Time Approach ; ◮ Slave Controller Design ; ◮ Results and Analysis ; � Linear Parameter-Varying System (LPV) : ◮ Polytopic-type uncertainties [B. Zhang et al., TDS, 2012] ; ◮ Norm-bounded uncertainties [B. Zhang et al., ROCOND, 2012] ; ◮ Results and Analysis ; 57 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Discrete-Time System : � x ( k + 1) = � q i =0 A i x ( k − τ i ( k )) + Bw ( k ) , (40) z ( k ) = Cx ( k ) . Delay-Free Case : � x ( k + 1) = A 0 x ( k ) + Bw ( k ) , (41) z ( k ) = Cx ( k ) . 58 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Robust Stability Condition : � Discrete LKF, y ( k ) = x ( k + 1) − x ( k ) : k − 1 k − 1 � � V ( x ( k )) = x ( k ) T Px ( k ) + x ( i ) T S a x ( i ) + x ( i ) T Sx ( i ) i = k − h 2 i = k − h 1 q − 1 k − 1 − h 1 − 1 k − 1 � � � � � y ( j ) T Ry ( j ) + y ( l ) T R ai y ( l ) . + h 1 ( h 2 − h 1 ) i = − h 1 j = k + i i =1 j = − h 2 l = k + j (42) � H ∞ control : J ( w ) = � ∞ i =0 [ z ( k ) T z ( k ) − γ 2 w ( k ) T w ( k )] < 0 � △ V ( x ( k )) = V ( x ( k + 1)) − V ( x ( k )) : △ V ( x ( k )) + z ( k ) T z ( k ) − γ 2 w ( k ) T w ( k ) < 0 . (43) � LMI condition is feasible (see manuscript) ; � Rate-independent asymptotically stable and H ∞ performance J ( w ) < 0 for time-varying delays τ i ( k ) ∈ [ h 1 , h 2 ] , h 2 ≥ h 1 ≥ 0 , i = 1 , 2 , ..., q ; 59 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach 3. Robustness Aspects � Discrete-Time System [B. Zhang et al., TDS, 2012] : ◮ Discrete-Time Approach ; ◮ Slave Controller Design ; ◮ Results and Analysis ; � Linear Parameter-Varying System (LPV) : ◮ Polytopic-type uncertainties [B. Zhang et al., TDS, 2012] ; ◮ Norm-bounded uncertainties [B. Zhang et al., ROCOND, 2012] ; ◮ Results and Analysis ; 60 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach System Description : (Σ d x m ( k + 1) = ( A md − B md K 0 m ) md ) x m ( k ) + B md ( F m ( k ) + F h ( k )) , (Σ d x s ( k + 1) = ( A sd − B sd K 0 s ) sd ) x s ( k ) + B sd ( F s ( k ) + F e ( k )) , (Σ d x p ( k + 1) = ( A md − B md K 0 p ) md ) x p ( k ) − B md F p ( k ) + B md ( ˆ τ 1 ( k )) + ˆ F e ( k − ˆ F h ( k − τ 1 ( k ))) . (44) 61 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Slave Controller Design - Master-Proxy Synchronization : � � � L d = L d 1 L d 2 L d 3 : � � ˙ θ p ( k − ˆ τ 1 ( k )) F p ( k ) = L d . (45) ˙ θ m ( k − τ 1 ( k )) θ p ( k − ˆ τ 1 ( k )) − θ m ( k − τ 1 ( k )) � = A 0 mpd x mp ( k ) + A 1 x mp ( k + 1) mpd x mp ( k − τ 1 ( k )) (Σ d mp ) (46) + B mpd w mp ( k ) , z mp ( k ) = C mpd x mp ( k ) , A 1 mpd = ⇒ L d ; 62 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Slave Controller Design - Proxy-Slave Synchronization : � � � K d = K d 1 K d 2 K d 3 : � � ˙ θ s ( k ) F s ( k ) = − K d ˙ . (47) θ p ( k ) θ s ( k ) − θ p ( k ) � � x ps ( k + 1) = A psd x ps ( k ) + B K F s ( k ) + B psd w ps ( k ) , (Σ d ps ) (48) z ps ( k ) = C psd x ps ( k ) , ⇓ � x ps ( k + 1) = ( A psd − B K K d ) x ps ( k ) + B psd w ps ( k ) , (¯ Σ d ps ) (49) z ps ( k ) = C psd x ps ( k ) . 63 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Slave Controller Design - Global Performance Analysis : � = A mpsd x ( k ) + B K mpsd F s ( k ) − B L x ( k + 1) mpsd F p ( k ) + B mpsd w ( k ) , (Σ d mps ) (50) = C mpsd x ( k ) , z ( k ) � � F s ( k ) = − ¯ K d x ( k ) = − x ( k ) , K d 1 K d 2 0 K d 3 0 � � F p ( k ) = ¯ L d x ( k − τ 1 ( k )) = x ( k − τ 1 ( k )) , 0 L d 1 L d 2 0 L d 3 (51) � B sd � � � 0 B md 0 B K B L mpsd = , mpsd = , 0 0 0 0 0 0 ⇓ � = A d 0 x ( k ) + A d x ( k + 1) 1 x ( k − τ 1 ( k )) + B mpsd w ( k ) , (¯ Σ d mps ) (52) = C mpsd x ( k ) , z ( k ) mpsd ¯ mpsd ¯ A d 0 = A mpsd − B K K d , A d 1 = − B L L d . 64 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach 3. Robustness Aspects � Discrete-Time System [B. Zhang et al., TDS, 2012] : ◮ Discrete-Time Approach ; ◮ Slave Controller Design ; ◮ Results and Analysis ; � Linear Parameter-Varying System (LPV) : ◮ Polytopic-type uncertainties [B. Zhang et al., TDS, 2012] ; ◮ Norm-bounded uncertainties [B. Zhang et al., ROCOND, 2012] ; ◮ Results and Analysis ; 65 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Simulation Conditions : � T = 0 . 001 s , h 1 = 1 , h 2 = 100 (in continuous-time domain, h 1 = 0 . 001 s , h 2 = 0 . 1 s ) ; � � � γ L d L d = 4 . 6815 − 5 . 1390 540 . 7828 , min = 0 . 0051 , � � (53) γ K d min = 2 . 9568 × 10 − 4 , K d = 273 − 127 10961 , γ g min = 0 . 0327 . 66 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Abrupt Tracking Motion : ♥ ♥ 67 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Abrupt Tracking Motion : ♥ ♥ 67 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Abrupt Tracking Motion : 68 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Wall Contact Motion : 69 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS Discrete-Time Approach Wall Contact Motion : 70 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Polytopic-Type Uncertainties 3. Robustness Aspects � Discrete-Time System [B. Zhang et al., TDS, 2012] : ◮ Discrete-Time Approach ; ◮ Slave Controller Design ; ◮ Results and Analysis ; � Linear Parameter-Varying System (LPV) : ◮ Polytopic-type uncertainties [B. Zhang et al., TDS, 2012] ; ◮ Norm-bounded uncertainties [B. Zhang et al., ROCOND, 2012] ; ◮ Results and Analysis ; 71 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Polytopic-Type Uncertainties System Description : x m ( t ) = ( A m ( ρ m ( t )) − B m ( ρ m ( t )) K 0 (Σ m ) ˙ m ) x m ( t ) + B m ( ρ m ( t ))( F m ( t ) + F h ( t )) , x s ( t ) = ( A s ( ρ s ( t )) − B s ( ρ s ( t )) K 0 (Σ s ) ˙ s ) x s ( t ) + B s ( ρ s ( t ))( F s ( t ) + F e ( t )) , x p ( t ) = ( A m ( ρ p ( t )) − B m ( ρ p ( t )) K 0 m ) x p ( t ) + B m ( ρ p ( t ))( ˆ τ 1 ( t )) + ˆ (Σ p ) ˙ F e ( t − ˆ F h ( t − τ 1 ( t )) − F p ( t )) , N N � � [ A m ( ρ m ( t )) , B m ( ρ m ( t ))] = ρ mj ( t )[ A mj , B mj ] , [ A s ( ρ s ( t )) , B s ( ρ s ( t ))] = ρ sj ( t )[ A sj , B sj ] , j =1 j =1 N � [ A m ( ρ p ( t )) , B m ( ρ p ( t ))] = ρ pj ( t )[ A mj , B mj ] . j =1 (54) 72 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Polytopic-Type Uncertainties Controller Design - Problem 1 : K 0 m & K 0 s : robust stability w.r.t polytopic-type uncertainties ; Controller Design - Problem 2 : L & K : stability & position/force tracking w.r.t time-varying delays & polytopic-type uncertainties ; Robust Stability Theorem [E. Fridman, IMA Journal of Mathematical Control and Information, 2006] : � P > 0 , R > 0 , S > 0 , S a > 0 , R ai > 0 , P 2 , P 3 , Y 1 , Y 2 , i = 1 , 2 , ..., q , and a positive scalar γ > 0 ; � N LMI conditions are feasible (see manuscript) ; � Rate-independent asymptotically stable with H ∞ performance J ( w ) < 0 for time-varying delays τ i ( t ) ∈ [ h 1 , h 2 ] , i = 1 , 2 , ..., q ; 73 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Polytopic-Type Uncertainties Problem 2 Slave Controller Design � Master-proxy synchronization : � = A 0 mp ( ρ mp ( t )) x mp ( t ) + A 1 x mp ( t ) ˙ mp ( ρ mp ( t )) x mp ( t − τ 1 ( t )) + B mp ( ρ mp ( t )) w mp ( t ) , z mp ( t ) = C mp x mp ( t ) , (55) K 0 m & K 0 ⇒ A 0 A 1 s = mp ( ρ mp ( t )) ; mp ( ρ mp ( t )) = ⇒ L ; � Proxy-slave synchronization : � x ps ( t ) ˙ = A ps ( ρ ps ( t )) x ps ( t ) + B ps ( ρ ps ( t )) w ps ( t ) , (56) z ps ( t ) = C ps x ps ( t ) , A ps ( ρ ps ( t )) = ⇒ K ; � Global performance analysis with K 0 m & K 0 s , L & K : = A 0 mps ( ρ mps ( t )) x mps ( t ) + A 1 x mps ( t ) ˙ mps ( ρ mps ( t )) x mps ( t − τ 1 ( t )) (57) + B mps ( ρ mps ( t )) w mps ( t ) , z mps ( t ) = C mps x mps ( t ) . 74 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Polytopic-Type Uncertainties Remark - Nonlinear Systems : M m ( θ m )¨ θ m ( t ) + C m ( θ m , ˙ θ m ) ˙ (Σ m ) θ m ( t ) + g m ( θ m ) = F h ( t ) + F m ( t ) , M m ( θ p )¨ θ p ( t ) + C m ( θ p , ˙ θ p ) ˙ θ p ( t ) + g m ( θ p ) = ˆ τ 1 ( t )) + ˆ (Σ p ) F e ( t − ˆ F h ( t − τ 1 ( t )) − F p ( t ) , M s ( θ s )¨ θ s ( t ) + C s ( θ s , ˙ θ s ) ˙ (Σ s ) θ s ( t ) + g s ( θ s ) = F e ( t ) + F s ( t ) , (58) ⇓ (¯ ¨ θ m ( t ) = A m ( θ m , ˙ θ m ) ˙ Σ m ) θ m ( t ) + B m ( θ m )( F h ( t ) + F m ( t ) − g m ( θ m )) , (¯ θ p ( t ) = A m ( θ p , ˙ ¨ θ p ) ˙ θ p ( t ) + B m ( θ p )( ˆ τ 1 ( t )) + ˆ Σ p ) F e ( t − ˆ F h ( t − τ 1 ( t )) − F p ( t ) − g m ( θ p )) , (¯ θ s ( t ) = A s ( θ s , ˙ ¨ θ s ) ˙ Σ s ) θ s ( t ) + B s ( θ s )( F e ( t ) + F s ( t ) − g s ( θ s )) , (59) θ m ) = − M − 1 B m ( θ m ) = M − 1 A m ( θ m , ˙ m ( θ m ) C m ( θ m , ˙ θ m ) , m ( θ m ) , θ p ) = − M − 1 B m ( θ p ) = M − 1 A m ( θ p , ˙ m ( θ p ) C m ( θ p , ˙ (60) θ p ) , m ( θ p ) , A s ( θ s , ˙ θ s ) = − M − 1 ( θ s ) C s ( θ s , ˙ B s ( θ s ) = M − 1 θ s ) , ( θ s ) . s s 75 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties 3. Robustness Aspects � Discrete-Time System [B. Zhang et al., TDS, 2012] : ◮ Discrete-Time Approach ; ◮ Slave Controller Design ; ◮ Results and Analysis ; � Linear Parameter-Varying System (LPV) : ◮ Polytopic-type uncertainties [B. Zhang et al., TDS, 2012] ; ◮ Norm-bounded uncertainties [B. Zhang et al., ROCOND, 2012] ; ◮ Results and Analysis ; 76 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties System Description : x m ( t ) = (( A m + ∆ A m ( t )) − ( B m + ∆ B m ( t )) K 0 (Σ m ) ˙ m ) x m ( t ) + ( B m + ∆ B m ( t ))( F m ( t ) + F h ( t )) , x s ( t ) = (( A s + ∆ A s ( t )) − ( B s + ∆ B s ( t )) K 0 (Σ s ) ˙ s ) x s ( t ) + ( B s + ∆ B s ( t ))( F s ( t ) + F e ( t )) , (61) x p ( t ) = (( A m + ∆ A p ( t )) − ( B m + ∆ B p ( t )) K 0 (Σ p ) ˙ m ) x p ( t ) − ( B m + ∆ B p ( t )) F p ( t ) + ( B m + ∆ B p ( t ))( ˆ τ 1 ( t )) + ˆ F e ( t − ˆ F h ( t − τ 1 ( t ))) , ∆( t ) T ∆( t ) � I. (62) i = { m, s, p } : ∆ A i ( t ) = G i ∆( t ) D i , ∆ B i ( t ) = H i ∆( t ) E i , 77 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties System Description : x m ( t ) = (( A m + ∆ A m ( t )) − ( B m + ∆ B m ( t )) K 0 (Σ m ) ˙ m ) x m ( t ) + ( B m + ∆ B m ( t ))( F m ( t ) + F h ( t )) , x s ( t ) = (( A s + ∆ A s ( t )) − ( B s + ∆ B s ( t )) K 0 (Σ s ) ˙ s ) x s ( t ) + ( B s + ∆ B s ( t ))( F s ( t ) + F e ( t )) , (63) x p ( t ) = (( A m + ∆ A p ( t )) − ( B m + ∆ B p ( t )) K 0 (Σ p ) ˙ m ) x p ( t ) − ( B m + ∆ B p ( t )) F p ( t ) + ( B m + ∆ B p ( t ))( ˆ τ 1 ( t )) + ˆ F e ( t − ˆ F h ( t − τ 1 ( t ))) , ∆( t ) T ∆( t ) � I. (64) i = { m, s, p } : ∆ A i ( t ) = G i ∆( t ) D i , ∆ B i ( t ) = H i ∆( t ) E i , Slave Controller Design Solution : Transformation from norm-bounded uncertain system to linear time-delay system ; 78 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties Problem 2 Slave Controller Design - Master-Proxy Synchronization : = ( A 0 mp + ∆ A 0 mp ( t )) x mp ( t ) + ( A 1 mp + ∆ A 1 x mp ( t ) ˙ mp ( t )) x mp ( t − τ 1 ( t )) +( B mp + ∆ B mp ( t )) w mp ( t ) , (65) z mp ( t ) = C mp x mp ( t ) , K 0 m & K 0 ⇒ A 0 mp + ∆ A 0 s = mp ( t ) ; ⇓ ϕ p ( t ) = (∆ A p ( t ) − ∆ B p ( t ) K 0 m ) ˙ θ p ( t ) + ∆ B p ( t )( ˆ τ 1 ( t )) + ˆ F e ( t − ˆ F h ( t − τ 1 ( t ))) , ϕ m ( t ) = (∆ A m ( t ) − ∆ B m ( t ) K 0 m ) ˙ (66) θ m ( t ) + ∆ B m ( t )( F m ( t ) + F h ( t )) , µ p ( t ) = − ∆ B p ( t ) Lx mp ( t − τ 1 ( t )) . � = A 0 mp x mp ( t ) + A 1 mp x mp ( t − τ 1 ( t )) + � x mp ( t ) ˙ B mp � w mp ( t ) , (67) z mp ( t ) = C mp x mp ( t ) , � � � 1 0 � Bm ˆ τ 1( t ))+ Bm ˆ Fe ( t − ˆ Fh ( t − τ 1( t ))+ ϕp ( t )+ µp ( t ) � w ( t ) = � , B mp = , (68) 0 1 BmFm ( t )+ BmFh ( t )+ ϕm ( t ) 0 0 A 1 mp = ⇒ L ; 79 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties Slave Controller Design - Proxy-Slave Synchronization : � x ps ( t ) ˙ = ( A ps + ∆ A ps ( t )) x ps ( t ) + ( B ps + ∆ B ps ( t )) w ps ( t ) , (69) z ps ( t ) = C ps x ps ( t ) , A ps + ∆ A ps ( t ) = ⇒ K ; ⇓ ϕ s ( t ) = (∆ A s ( t ) − ∆ B s ( t ) K 0 s ) ˙ θ s ( t ) + ∆ B s ( t ) F e ( t ) , (70) µ s ( t ) = − ∆ B 1 ps ( t ) Kx ps ( t ) . � = A ps x ps ( t ) + � x ps ( t ) ˙ B ps � w ps ( t ) , (71) z ps ( t ) = C ps x ps ( t ) , � � � 1 0 � BsFe ( t )+ ϕs ( t )+ µs ( t ) � w ps ( t ) = � , B ps = , 0 1 Bm ˆ τ 1( t ))+ Bm ˆ Fe ( t − ˆ Fh ( t − τ 1( t )) − BmFp ( t )+ ϕp ( t )+ µp ( t ) 0 0 (72) A ps = ⇒ K ; 80 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties Slave Controller Design - Global Performance Analysis : = ( A 0 mps + ∆ A 0 mps ( t )) x mps ( t ) + ( A 1 mps + ∆ A 1 x mps ( t ) ˙ mps ( t )) x mps ( t − τ 1 ( t )) (73) +( B mps + ∆ B mps ( t )) w mps ( t ) , z mps ( t ) = C mps x mps ( t ) . ⇓ � = A 0 mps x mps ( t ) + A 1 mps x mps ( t − τ 1 ( t )) + � x mps ( t ) ˙ B mps � w mps ( t ) , (74) z mps ( t ) = C mps x mps ( t ) , � � 1 0 0 BsFe ( t )+ ϕs ( t ) 0 1 0 Bm ˆ τ 1( t ))+ Bm ˆ � . w mps ( t ) = � Fe ( t − ˆ Fh ( t − τ 1( t ))+ ϕp ( t ) , B mps = (75) 0 0 1 0 0 0 BmFm ( t )+ BmFh ( t )+ ϕm ( t ) 0 0 0 81 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties 3. Robustness Aspects � Discrete-Time System [B. Zhang et al., TDS, 2012] : ◮ Discrete-Time Approach ; ◮ Slave Controller Design ; ◮ Results and Analysis ; � Linear Parameter-Varying System (LPV) : ◮ Polytopic-type uncertainties [B. Zhang et al., TDS, 2012] ; ◮ Norm-bounded uncertainties [B. Zhang et al., ROCOND, 2012] ; ◮ Results and Analysis ; 82 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties Simulation Conditions : � polytopic − type : A m ( ρ m ( t )) = A s ( ρ s ( t )) = 0 , 1 B m ( ρ m ( t )) = B s ( ρ s ( t )) = , ρ ( t ) ∈ [0 . 5 , 1] , ρ ( t ) (76) norm − bounded − type : A m = A s = 0 , G i = D i = 0 , B m = B s = 1 . 5 , H i = 0 . 5 , E i = 1 , i = { m, p, s } . � K 0 K 0 polytopic − type : m = 2 . 6585 , s = 2 . 6585 , (77) K 0 K 0 norm − bounded − type : m = 9 . 5117 , s = 3 . 3812 . � � � γ L polytopic − type : L = 1 . 3218 − 1 . 3219 6 . 3602 , min = 0 . 4436 , � � γ K K = min = 0 . 0164 , 20 . 4799 − 21 . 2537 575 . 2051 , γ g min = 0 . 4595 , (78) � � γ L norm − bounded − type : L = 1 . 6218 − 1 . 6264 29 . 5012 , min = 0 . 05 , � � γ K K = 16 . 4993 − 12 . 0059 434 . 4988 , min = 0 . 0072 , γ g min = 0 . 0376 . 83 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties Abrupt Tracking Motion : 84 / 102
New Control Schemes for Bilateral Teleoperation under Asymmetric Communication Channels ROBUSTNESS H ∞ Robust Teleoperation under Time-Varying Model Uncertainties - Norm-Bounded Model Uncertainties Wall Contact Motion : 85 / 102
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