Realisation of model reference compliance control of a humanoid robot arm via integral sliding mode control

Abstract

Abstract. Human safety becomes critical when robot enters the human environment. Compliant control can be used to address some safety issues in human-robot physical interaction. This paper proposes an integral sliding mode controller (ISMC) based compliance control scheme for the Bristol Robotics Laboratory's humanoid BERT II robot arm. Apart from introducing a model reference compliance controller, the ISMC scheme is aimed to deal with the robot arm dynamic model's inaccuracies and un-modelled nonlinearities. The control scheme consists of a feedback linearization (FL) and an ISMC part. In addition, a posture controller has been incorporated to employ the redundant DOF and generate human like motion. The desired level of compliance can be tuned by selecting the stiffness and damping parameters in the sliding mode variable (compliance reference model). The results show that the compliant control is feasible at different levels for BERT II in simulation and experiment. The positioning control has been satisfactorily achieved and nonlinearities and un-modelled dynamics have been successfully overcome.

Chaos Stabilization and Tracking Recovery of a Faulty Humanoid Robot Arm in a Cooperative Scenario

“…It follows that e m (0) andė m (0) are the initial Cartesian position and velocity errors, respectively. According to [29], the integral sliding mode variable can be defined as…”

“…where K p and K d are 2 × 2 real matrices representing the proportional and derivative gains, respectively, α > 0 is a sufficiently large scalar aimed at minimizing the effect of uncertainty and improving the robustness of the SMC controller [29], and ζ is an appropriately selected scalar that minimizes the effect of chattering. The controller described in Equation ( 8) is well studied in the literature and given a multistep demand X d (n) results in the response depicted in Figure 4.…”

Nonlinear control systems - A brief overview of historical and recent advances

“…Based on ISMC law, Khan and Jalani proposed and experimentally validated a scheme for a humanoid robot arm control. They have also demonstrated compliance control via this scheme employing joint torque sensors [47]. The scheme is illustrated in Fig.…”

Robust Tracking and Human-Compliance Control Using Integral SMC and DOB

“…로봇은 상황에 따라서 저임피던스와 고임피 던스를 갖도록 해야한다 [4][5][6]. 즉 인간과의 접촉이 없 는 경우에는 고임피던스를 가져야 하고 로봇과 인간이 접촉하게 되는 경우에는 안전성을 고려해서 저임피던 스의 순응성을 가질 수 있도록 두가지 상반된 기능을 동시에 만족시켜야 한다 [7][8][9][10]. 참고 [7] …”