Regulated Sliding Mode Control of a Biped Robot

Moosavian, S. Ali A.; Takhmar, Amir; Asif, Mansoor

doi:10.1109/icma.2007.4303779

Cited by 21 publications

(15 citation statements)

References 14 publications

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“…13 and 14, both measures (MHS and ZMP) predict the same time for tip-over initialization (at the time about 1.4 S where both measures become zero), yet the MHS alerts the system or its operator (in the case of teleportation) by its gradual decrease. Note that in contrast to the ZMP, which does not provide any valid information during the phase of fall, [1][2], MHS is proportional to the severity of instability and indicating the tip-over angular acceleration.…”

Section: B Mhs Measure Response Explorationmentioning

confidence: 97%

“…Vukobratovic has introduced the prescribed synergy method to design the upper body motion considering stability factor, [1]. A stable trajectory for a biped robot and implementation of a Regulated Sliding Mode Control (SMC) on the biped robot has been also proposed, [2]. However, it should be noted that the most important factor in investigation of biped robots is the stability consideration.…”

Section: Introductionmentioning

confidence: 98%

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MHS measure for postural stability monitoring and control of biped robots

Takhmar

Asif

Alipour

et al. 2008

2008 IEEE/ASME International Conference on Advanced Intelligent Mechatronics

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Stability fulfilment for biped robots is drastically essential. Thus, to predict and maintain a dynamic stable status of biped robots defining an accurate stability measure is required which can represent dynamic equilibrium condition. Several postural stability metrics have been proposed so far. In this article, the Moment-Height stability (MHS) measure which has been previously proposed for wheeled mobile robots is developed for biped robot control. The responses of this criterion for stability monitoring of a biped robot is compared with the well known stability criterion Zero-Moment Point (ZMP). To this end, two common case studies of robot's motion including standing up and walking are considered and the results of application of the MHS are compared with those of the ZMP. The obtained results reveal the merits of MHS over ZMP in terms of its higher sensitivity to walking height (overall height of the robot's center of mass) and indicating the direction of foot rotation. The MHS metric is able not only to monitor the state of postural stability of a biped robot during the entire gait cycle, but also it does reliably indicate the severity of instability of the gait.

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Section: B Mhs Measure Response Explorationmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

MHS measure for postural stability monitoring and control of biped robots

Takhmar

Asif

Alipour

et al. 2008

2008 IEEE/ASME International Conference on Advanced Intelligent Mechatronics

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“…Then, generated trajectories in the task space are projected into the joint space to yield desired joint trajectories, using inverse kinematics 12 . Finally, the low-level control system is responsible for tracking the obtained desired trajectories [13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Online adaptation for humanoids walking on uncertain surfaces

Khadiv

Moosavian

Yousefi‐Koma

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part I:

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In this paper, an online adaptation algorithm for bipedal walking on uneven surfaces with height uncertainty is proposed. In order to generate walking patterns on flat terrains, the trajectories in the task space are planned to satisfy the dynamic balance and slippage avoidance constraints, and also to guarantee smooth landing of the swing foot. To ensure smooth landing of the swing foot on surfaces with height uncertainty, the preplanned trajectories in the task space should be adapted.The proposed adaptation algorithm consists of two stages. In the first stage, once the swing foot reaches its maximum height, the supervisory control is initiated until the touch is detected. After the detection, the trajectories in the task space are modified to guarantee smooth landing. In the second stage, this modification is preserved during the Double Support Phase (DSP), and released in the next Single Support Phase (SSP). Effectiveness of the proposed online adaptation algorithm is experimentally verified through realization of the walking patterns on the SURENA III humanoid robot, designed and fabricated at CAST. The walking is tested on a surface with various flat obstacles, where the swing foot is prone to either land on the ground soon or late.

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“…10 Moosavian et al have presented various studies on dynamics modeling of a planar seven-link biped robot in joint space and its control in single and double support phase. 11,12 However, some studies on design of stable gait planning include design in both joint and task spaces. It means, some points are considered as the important points in the task space and then by using various methods and novelties, their trajectories are calculated.…”

Section: Introductionmentioning

confidence: 99%

Cartesian Approach for Gait Planning and Control of Biped Robots on Irregular Surfaces

Moosavian

Asif

Takhmar

2009

Int. J. Human. Robot.

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Biped robots possess higher capabilities than other mobile robots for moving on uneven environments. However, due to natural postural instability of these robots, their motion planning and control become a more important and challenging task. This article presents a Cartesian approach for gait planning and control of biped robots without the need to use the inverse kinematics and the joint space trajectories, thus the proposed approach could substantially reduce the processing time in both simulation studies and online implementations. It is based on constraining four main points of the robot in Cartesian space. This approach exploits the concept of Transpose Jacobian control as a virtual spring and damper between each of these points and the corresponding desired trajectory, which leads to overcome the redundancy problem. These four points include the tip of right and left foot, the hip joint, and the total center of mass (CM). Furthermore, in controlling biped robots based on desired trajectories in the task space, the system may track the desired trajectory while the knee is broken. This problem is solved here using a PD controller which will be called the Knee Stopper. Similarly, another PD controller is proposed as the Trunk Stopper to limit the trunk motion. Obtained simulation results show that the proposed Cartesian approach can be successfully used in tracking desired trajectories on various surfaces with lower computational effort.

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Regulated Sliding Mode Control of a Biped Robot

Cited by 21 publications

References 14 publications

MHS measure for postural stability monitoring and control of biped robots

MHS measure for postural stability monitoring and control of biped robots

Online adaptation for humanoids walking on uncertain surfaces

Cartesian Approach for Gait Planning and Control of Biped Robots on Irregular Surfaces

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