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

Abstract

Synchronised motion is an important requirement for two cooperating humanoid robot arms. In this work a cooperative scenario is considered where two humanoid robot arms (using 4DOF each, namely Shoulder Flexion Joint, Shoulder abduction Joint, Humeral rotation joint and Elbow Flexion Joint) motion are synchronized. The master robot arm is controlled by a sliding mode controller and the slave robot arm is synchronized using a basic PD plus adaptive control, employing the position and velocity errors between the master and the slave. During the operation, if a joint of the slave robot arm saturates or malfunctions (for instance, Elbow flexion joint does not respond or free swinging), consequently, slave robot arm will go into chaos (i.e., chaotic motion of the end effector). In this case, a chaos controller kicks in to recover and re-synchronize the motion of the slave robot arm end effector. This re-synchronization is extremely important to complete the task in hand to address any safety issues arising from any joint malfunction of the slave robot. Effectiveness of the scheme is tested in simulation using Bristol Robotics Laboratory Humanoid BERT II arms.

Adaptive chaos control of a humanoid robot arm: a fault-tolerant scheme

“…In recent years, chaos has found its way into numerous applications within the robotics field including mobile robots and robotic manipulators (Petavratzis et al, 2023;Yang et al, 2023;Khan et al, 2019). A good summary of some of these applications can be found in the work by Zang et al (2016).…”

“…This is easy to observe as will be shown in the next section. In order to overcome this chaotic behavior, a stabilization controller based on the energy altering technique presented in Tereshko (2009) is employed (see also Khan et al, 2019), in conjunction with the SMC control law (Eq. 4).…”

“…Khan et al (2019) have implemented a model reference compliance controller (Khan et al, 2010b(Khan et al, , a, 2011aJallani et al, 2011;Herrmann et al, 2016;Khan and Jalani, 2016;Spiers et al, 2016) for master slave robot cooperation to deal with an actuator fault. In contrast to the work by Khan et al (2019), in this work, the chaos element is adaptive and self-tuned. This makes it more beneficial to deal with the situation more effectively.…”