Turning strategy analysis based on trot gait of a quadruped robot

Wan, Lei; Zhou, Liguang; Qian, Huihuan; Xu, Yangsheng

doi:10.1109/robio.2017.8324598

Cited by 10 publications

(5 citation statements)

References 15 publications

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“…A 3D-SLIP model was developed for high-speed turning by a humanoid robot while running at 4.0 m s −1 in a simulation, but no empirical experiment was conducted [26]. Precise turning gait generation methods have been proposed for quadruped robots based on geometrical constraints [27,28]. Using optimization-based predictive control and a data-driven heuristic, MIT's cheetah can perform a rapid turn at 2 rad sec −1 while moving at a speed of 1.5 m sec −1 [29].…”

Section: Introductionmentioning

confidence: 99%

Dynamic turning and running of a hexapod robot using a separated and laterally arranged two-leg model

Chang¹,

Lin²

2023

Bioinspir. Biomim.

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We report on the development of separated and laterally arranged two-leg (SLTL) models with/without differentiated leg properties and their use as the dynamic running and turning templates for a hexapod robot. The laterally arranged two-leg morphology enables differential driving for turning. The differentiable leg settings, such as stiffness, enables the model to adopt unbalanced leg arrangements of empirical legged gaits, such as a tripod gait, into consideration. The fixed-point motion of the model was utilized as the main methodology to plan dynamic running and turning, in which the plot of one-step distance versus period was constructed for the legs’ operation point selection and matching. The proposed methodology was experimentally validated using four indices: turning curvature, flight phase, motion stability, and energy efficiency. The experimental results show that the running robot using the SLTL model with differentiated leg stiffness has better energy efficiency than one without by 4%, while the latter model has identical performance to the original spring-loaded inverted pendulum model with rolling contact. As for turning, the robot using the SLTL models with/without differentiated leg stiffness can preserve dynamic turning in all experiments with turning curvatures up to 0.28m^(-1) and 0.30m^(-1), respectively, 33% and 43% more than the robot using the original model-less phase-shift turning strategy (0.21 m^(-1)). Using the proposed model-based strategy, the flight phase of the robot turning in all curvatures (including straight running) maintains around 20%, the root-mean-squared (RMS) values of pitch and roll remains less than 3 deg, and the specific resistance (SR) is bounded between 0.64 and 0.73. By contrast, the robot using the phase-shifting turning strategy can maintain dynamic motion up to a turning curvature of 0.21 m^(-1). A further increase in phase shifting not only does not increase the turning curvature but also changes the robot motion from running to walking. In this case, no flight phase exists, the SR jumps up significantly, and RMS values of pitch and roll also increase dramatically. In short, the experimental validation confirms the effectiveness of the proposed methodology for initiating the dynamic running and turning of the robot.

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Section: Introductionmentioning

confidence: 99%

Dynamic turning and running of a hexapod robot using a separated and laterally arranged two-leg model

Chang¹,

Lin²

2023

Bioinspir. Biomim.

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“…To address this challenge, this study first proposes a gait planning method with a modeled spherical foot for turning and spinning in the trotting gait. Based on the geometrical relationship of the foot end effector and body coordinate, a desired turning foot position is generated ( Palmer and Orin, 2006 ; Roy and Pratihar, 2012 ; Liu et al, 2017 ). A spinning gait is obtained when the turning radius becomes zero.…”

Section: Introductionmentioning

confidence: 99%

Terrain-Perception-Free Quadrupedal Spinning Locomotion on Versatile Terrains: Modeling, Analysis, and Experimental Validation

et al. 2021

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Dynamic quadrupedal locomotion over rough terrains reveals remarkable progress over the last few decades. Small-scale quadruped robots are adequately flexible and adaptable to traverse uneven terrains along the sagittal direction, such as slopes and stairs. To accomplish autonomous locomotion navigation in complex environments, spinning is a fundamental yet indispensable functionality for legged robots. However, spinning behaviors of quadruped robots on uneven terrain often exhibit position drifts. Motivated by this problem, this study presents an algorithmic method to enable accurate spinning motions over uneven terrain and constrain the spinning radius of the center of mass (CoM) to be bounded within a small range to minimize the drift risks. A modified spherical foot kinematics representation is proposed to improve the foot kinematic model and rolling dynamics of the quadruped during locomotion. A CoM planner is proposed to generate a stable spinning motion based on projected stability margins. Accurate motion tracking is accomplished with linear quadratic regulator (LQR) to bind the position drift during the spinning movement. Experiments are conducted on a small-scale quadruped robot and the effectiveness of the proposed method is verified on versatile terrains including flat ground, stairs, and slopes.

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“…However, it is well known that tetrapods in nature usually twist, dive or bend their trunks to walk, run or crawl [18][19][20]. The turning strategy of a four-legged robot based on leg gait was mentioned by Liu et al [21]. The transition between single supporting leg of the four-legged robot and walking posture was studied by Zhang et al [22].…”

Section: Introductionmentioning

confidence: 99%

Kinematics analysis of a FLHL robot parallel-executed cylinder mechanical integration system with force/position hybrid control servo actuator

Wang¹,

Wang²,

Fu³

et al. 2021

J. vibroeng.

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In this research subtopic, an electro-hydraulic servo four-legged heavy load (FLHL) robot has been designed and developed. This paper proposes an integration layout cylinder design scheme for a non-lightweight hydraulic servo four-legged robot with high loads and torques of hip joint, and derives the mathematical element analysis model for a parallel hydraulic servo cylinder system. The multiple inherent characteristics of the parallel-executed cylinder integration system model are further explored. Based on the controllable functional requirements of interconnected joints and weakening the influence of internal force coupling, a design idea of force/position hybrid control scheme for the parallel-executed cylinder is determined, and then the force/position signal module design unit is used to reversely solve the force/position hybrid control. Considering the inherent requirements of the servo-executed cylinder force control unit module, the implementation process of magnetic flux compensation and speed compensation is discussed in detail. The minimum amplitude controller is applied to the servo-executed cylinder force unit module, and the proportional integrated controller has been determined in the servo-executed cylinder position control unit module. A compound control strategy proposed in this paper is verified on a parallel hydraulic servo platform. The experimental verification results reveal that the values of position/force attenuation amplitude and lag phase are not greater than 9 % and 18°, respectively. In addition, the feasibility of the interconnected implementation of the hybrid control scheme proposed in this paper is further deepened. The effective conclusion of this research will be accepted in the application field of FLHL robot control system.

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Turning strategy analysis based on trot gait of a quadruped robot

Cited by 10 publications

References 15 publications

Dynamic turning and running of a hexapod robot using a separated and laterally arranged two-leg model

Dynamic turning and running of a hexapod robot using a separated and laterally arranged two-leg model

Terrain-Perception-Free Quadrupedal Spinning Locomotion on Versatile Terrains: Modeling, Analysis, and Experimental Validation

Kinematics analysis of a FLHL robot parallel-executed cylinder mechanical integration system with force/position hybrid control servo actuator

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