Application of nonlinear adaptive control techniques to an electrohydraulic velocity servomechanism

Adaptive sliding mode control of electro-hydraulic system with nonlinear unknown parameters

“…The effects of servo valve dynamics have been included in some literatures , but this requires an additional sensor to obtain the spool position and only minimal performance improvement is achieved for position tracking, so other researchers neglect servo valve dynamics according to practice status, (Garagic & Srinivasan, 2004;Liu & Handroos, 1999). Since a high-response servo valve is used here, it is assumed that the control applied to the spool valve is directly proportional to the spool position, then the following equation is given by…”

“…Adaptive control is a valid method to overcome system uncertainties, especially uncertainties derived from uncertain parameters; hence several kinds of nonlinear adaptive control schemes have been proposed in hydraulic control systems such as feedback linearization adaptive control (Garagic & Srinivasan, 2004), sliding mode adaptive control (Guan & Zhu, 2004), and nonlinear adaptive control based on backstepping techniques Yao, Bu, & Chiu, 1998;Yao, Bu, Reedy, & Chiu, 2000). For example, Alleyne and Liu (2000) and Liu and Alleyne (2000) applied the nonlinear adaptive control based on the backstepping method to the force control of electrohydraulic system, B.…”

Adaptive robust dead-zone compensation control of electro-hydraulic servo systems with load disturbance rejection

“…Combine (2), (3), (4), (8) and choose state variable as x 1 = x L , x 2 =ẋ L , x 3 = P L , the system dynamic state function can be described as…”

“…But frictions and external load disturbances tend to degrade the performance of feedback linearization based control. Adaptive methods are applied to the feedback linearization [3,8] , the performance is enhanced via compensation for the uncertainties and nonlinearities. However, the use of adaptive feedback linearization method requires a companion form in the model dynamic which is not easy to get especially when dead-zones in the servo valve is considered.…”

Model-based control of a 6-dof electrohydraulic Stewart–Gough platform

“…Nonlinear adaptive control techniques for hydraulic servosystems have been proposed by Garagic and Srinivasan assuming linearization [13], and by Sirouspour and Salcudean using backstepping [14], approaches. The modelling of an experimental hydraulic robot arm and the implementation of a model-based motion controller that compensates for dynamic forces have been presented by Honegger and Corke [15].…”