Fariz Ali

Center of mass based inverse kinematics algorithm for bipedal robot motion on inclined surfaces

Nowadays, humanoid researches are progressing widely in many applications. Some of the applications are walking in human environments such as on stairs and inclined floor. In order to solve this, there are researchers who implemented ankle torque control approach. However, by implementing this approach, it may saturate the ankle joints and if too much force is applied, it may damage the ankle joints. Therefore, the authors¿ group proposed an approach to distribute the angles caused by the inclined surfaces via distribution among the robot joints. The orientations of CoM or pelvis of the robot can be embedded into the inverse kinematics in order to achieve successful walking on inclined surfaces. A 3-D dynamic simulator which is known as ROCOS and developed in our laboratory is used for simulation in order to validate our proposed method.

Bipedal robot walking strategy on inclined surfaces using position and orientation based inverse kinematics algorithm

This paper proposes a strategy for bipedal robot walking on inclined surfaces using position and orientation based inverse kinematics algorithm. Some researchers implemented control approaches to solve bipedal walking on inclined surfaces. Generally, most of them apply control feedback at ankle joints and also introduced many more control methodologies. In this paper, inverse kinematics methodology is introduced systematically for bipedal walking on inclined floor. Positions and orientations are embedded into the kinematics calculation. In this strategy, a working bipedal robot walking pattern for flat floor must be developed first. Then, the same walking pattern can be used for the inclined floor with orientation included so that the bipedal robot is able to walk on the inclined floor successfully. This methodology will distribute the angles caused by the inclined surfaces to the appropriate robot joints. By doing this, control at ankle joints only is avoided. A 3-D dynamics simulator which is known as Robot Control Simulator and developed in our laboratory is used for simulation in order to validate our proposed method.

Slope-walking of a biped robot with position and orientation based inverse kinematics method

This paper proposes a slope-walking strategy of a bipedal robot using position and orientation based inverse kinematics method. Some researchers implemented control approaches to solve this problem. Generally, they apply control feedback at ankle joints and introduced many more control methodologies. Several researchers used pelvis and foot trajectories without showing center of mass trajectory. In this paper, a constant center of mass height trajectory of a biped robot during slope walking is ensured. Inverse kinematics methodology is introduced systematically for bipedal walking on inclined floor. Positions and orientations are embedded into the kinematics calculation. In this strategy, walking pattern for flat floor must be developed first. Then, the same walking pattern can be used for the inclined floor with orientation included so that the bipedal robot is able to walk on the inclined floor successfully. This methodology will distribute the angles caused by the inclined surfaces to the appropriate robot joints. By doing this, control at ankle joints only is avoided. 3-D dynamics simulator, known as Robot Control Simulator is used for simulations in order to validate our proposed method. Simulations of biped walking on 11° slope with our proposed method have been done.

Constant pelvis height ZMP-based walking: A study on energy consumption during walking

Researchers introduced a constant center of mass walking, mainly to solve the ZMP equations analytically for center of mass trajectories in the x and y directions (case 1). In this paper, case 2 proposes that if pelvis is made constant instead, energy usage could be reduced particularly at the leg joints. CoM-based kinematics methods are used to realize each case. Walking simulations of 0.22km/h are utilized for observations. In the simulation results, case 2 consumed almost 12% less in total energy consumption (electrical and mechanical) compared to case 1.

An improved trajectory of biped robot for walking along slope

A bipedal robot should be robust and able to move in various directions on slope or stairs. However, up to date many research studies have been focussing on walking in the up or down direction only. Therefore, a strategy to realize walking along slope is investigated. In conventional methods, CoM is moved up and down during walking in this situation. In this paper, a method named as dual length linear inverted pendulum method with Newton-Raphson is proposed in order to move CoM always in horizontal. Different lengths of pendulums are applied at left and right legs in order to represent the CoM height. By using the proposed method, maximum impact forces are reduced as verified via the simulation results.