Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height.This paper investigates the performance of a radial symmetrical hexapod...Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height.This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism.Assuming the constraints between the supporting feet and the ground with hinges,the supporting legs and the hexapod body are taken as a parallel mechanism,and each swing leg is regarded as a serial manipulator.The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground.Locomotion performance can be got by analyzing these equivalent mechanisms.The kinematics of the whole robotic system is established,and the influence of foothold position on the workspace of robot body is analyzed.A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle.Referring to service region and service sphere,weight service sphere and weight service region are put forward to evaluate the dexterity of robot body.The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated.Simulation shows when the foothold offset goes up to 174 mm,the dexterity of robot body achieves its maximum value 0.164 4 in mixed gait.The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot,and provide new approach to determine the stride length,body height,footholds in gait planning of multi-legged robot.展开更多
Robots are widely used to replace people in some burdensome or hamaful areas. Not only the moving ability but also the manipulating ability is needed in the missions of complex multitasking requirements. In the last d...Robots are widely used to replace people in some burdensome or hamaful areas. Not only the moving ability but also the manipulating ability is needed in the missions of complex multitasking requirements. In the last decades, wheel-legged hexapod robots are extensively studied to ineet this condition.展开更多
Realistically there are many robot joints in the biologically inspired hexapod robot, so they will generate many complexities in the calculations of the gait and the path planning and the control variables. The softwa...Realistically there are many robot joints in the biologically inspired hexapod robot, so they will generate many complexities in the calculations of the gait and the path planning and the control variables. The software Solidworks and MSC. ADAMS are adopted to simulate and analyze the prototype model of the robot. By the simulations used in our design, the applicability of the tripod gait is validated, and the scheme which uses cubic spline curve as the endpoint of foot＇s path is feasible. The principles, methods, and processes of the simulation of hexapod robot are illustrated. A methodology is proposed to get the robot inverse solution in ADAMS, and to simplify the theoretical calculation, and further more to improve the efficiency of the design.展开更多
To provide hexapod robots with strategies of locomotion planning, observation experiments were operated on a kind of ant with the use of high speed digital photography and computer assistant analysis. Through digitali...To provide hexapod robots with strategies of locomotion planning, observation experiments were operated on a kind of ant with the use of high speed digital photography and computer assistant analysis. Through digitalization of original analog video, locomotion characters of ants were obtained, the biomimetic foundation was laid for polynomial trajectory planning of multi-legged robots, which was deduced with mathematics method. In addition, five rules were concluded, which apply to hexapod robots marching locomotion planning. The first one is the fundamental strategy of multi-legged robots＇ leg trajectory planning. The second one helps to enhance the static and dynamic stability of multi-legged robots. The third one can improve the validity and feasibility of legs＇ falling points. The last two give criterions of multi-legged robots＇ toe trajectory figures and practical recommendatory constraints. These five rules give a good method for marching locomotion planning of multi-legged robots, and can be expended to turning planning and any other special locomotion.展开更多
In order to enhance the innervation fidelity of simulators,a nonlinear controller is developed,which guarantees parallel mechanisms closed loop system global asymptotical stability and the convergence of posture track...In order to enhance the innervation fidelity of simulators,a nonlinear controller is developed,which guarantees parallel mechanisms closed loop system global asymptotical stability and the convergence of posture tracking error in Cartesian space. The problems of rapid tracking under the condition of the wide range,nonlinear and variable load are solved. After the nonlinear controller is actually applied to the hexapod parallel mechanisms of simulator,the dynamic-static capabilities of motion system are tested by amplitude-frequency response and posture precision. The experimental results show that the static precision improves ten times and system output amplitude increases and the phase lag reduces with respect to the same input signal in Cartesian space in comparison with the traditional proportional and derivative (i.e. PD) controlling method in joint space. Therefore the nonlinear controller can effectively improve the dynamic-static response performance of the hexapod parallel mechanisms of simulators in Cartesian space.展开更多
The adapotation of gaits pattern is a basic and important for the hexapod robot to move stably and efficiently,which depends on the servos of the robot’s legs,and also the body structure of the robot.This paper compa...The adapotation of gaits pattern is a basic and important for the hexapod robot to move stably and efficiently,which depends on the servos of the robot’s legs,and also the body structure of the robot.This paper compares the tripod gait and the crab-inspired gait for a specific hexapod to move forward and move backward;turn left and turn right and integrates the two gaits to apply them under different conditions.The hexapod has three servos on each legs,thus the freedom level of each leg is three-degree.From the comparative experiment,this two gait patterns are suitable for different turning demands.展开更多
Small inspection robots allow for the optimal exploration of environments and the collection of data from challenging areas,particularly where there may be small access points or tight and fragile surroundings.These r...Small inspection robots allow for the optimal exploration of environments and the collection of data from challenging areas,particularly where there may be small access points or tight and fragile surroundings.These robots can be custom-built for specific tasks,but the design and assembly process for this can be costly,both in resources and assembly time.The use of 3D printing to create Non-Assembly mechanisms can assist in saving time and resources by reducing the number of different components required and removing the necessity for complex assembly tasks.By iterating on previous work performed in the institute,this paper introduces a novel robot design to push the capabilities of Non-Assembly systems.By building on previous knowledge,this new walking robot improves on the previous iteration by creating a more robust and reliable system,more capable of effectively exploring challenging environments accurately,while still using practices designed to save on cost and production time.Benchmark tests were performed to provide an accurate comparison against the previous design and highlight the robots marked improvements in positional accuracy over its predecessor.展开更多
基金Supported by National Science Foundation for Distinguished Young Scholar,China(Grant No.51125020)National Natural Science Foundation of China(Grant No.51305009)CAST Foundation
文摘Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height.This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism.Assuming the constraints between the supporting feet and the ground with hinges,the supporting legs and the hexapod body are taken as a parallel mechanism,and each swing leg is regarded as a serial manipulator.The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground.Locomotion performance can be got by analyzing these equivalent mechanisms.The kinematics of the whole robotic system is established,and the influence of foothold position on the workspace of robot body is analyzed.A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle.Referring to service region and service sphere,weight service sphere and weight service region are put forward to evaluate the dexterity of robot body.The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated.Simulation shows when the foothold offset goes up to 174 mm,the dexterity of robot body achieves its maximum value 0.164 4 in mixed gait.The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot,and provide new approach to determine the stride length,body height,footholds in gait planning of multi-legged robot.
文摘Robots are widely used to replace people in some burdensome or hamaful areas. Not only the moving ability but also the manipulating ability is needed in the missions of complex multitasking requirements. In the last decades, wheel-legged hexapod robots are extensively studied to ineet this condition.
基金Sponsored by the Ministerial Level Advanced Research Foundation(6140528)
文摘Realistically there are many robot joints in the biologically inspired hexapod robot, so they will generate many complexities in the calculations of the gait and the path planning and the control variables. The software Solidworks and MSC. ADAMS are adopted to simulate and analyze the prototype model of the robot. By the simulations used in our design, the applicability of the tripod gait is validated, and the scheme which uses cubic spline curve as the endpoint of foot＇s path is feasible. The principles, methods, and processes of the simulation of hexapod robot are illustrated. A methodology is proposed to get the robot inverse solution in ADAMS, and to simplify the theoretical calculation, and further more to improve the efficiency of the design.
基金Sponsored by the Ministerial Level Advanced Research Foundation(65822576)
文摘To provide hexapod robots with strategies of locomotion planning, observation experiments were operated on a kind of ant with the use of high speed digital photography and computer assistant analysis. Through digitalization of original analog video, locomotion characters of ants were obtained, the biomimetic foundation was laid for polynomial trajectory planning of multi-legged robots, which was deduced with mathematics method. In addition, five rules were concluded, which apply to hexapod robots marching locomotion planning. The first one is the fundamental strategy of multi-legged robots＇ leg trajectory planning. The second one helps to enhance the static and dynamic stability of multi-legged robots. The third one can improve the validity and feasibility of legs＇ falling points. The last two give criterions of multi-legged robots＇ toe trajectory figures and practical recommendatory constraints. These five rules give a good method for marching locomotion planning of multi-legged robots, and can be expended to turning planning and any other special locomotion.
基金Sponsored by the Ministry of Education Science and Technology Research Key Project (Grant No.03055)
文摘In order to enhance the innervation fidelity of simulators,a nonlinear controller is developed,which guarantees parallel mechanisms closed loop system global asymptotical stability and the convergence of posture tracking error in Cartesian space. The problems of rapid tracking under the condition of the wide range,nonlinear and variable load are solved. After the nonlinear controller is actually applied to the hexapod parallel mechanisms of simulator,the dynamic-static capabilities of motion system are tested by amplitude-frequency response and posture precision. The experimental results show that the static precision improves ten times and system output amplitude increases and the phase lag reduces with respect to the same input signal in Cartesian space in comparison with the traditional proportional and derivative (i.e. PD) controlling method in joint space. Therefore the nonlinear controller can effectively improve the dynamic-static response performance of the hexapod parallel mechanisms of simulators in Cartesian space.
文摘The adapotation of gaits pattern is a basic and important for the hexapod robot to move stably and efficiently,which depends on the servos of the robot’s legs,and also the body structure of the robot.This paper compares the tripod gait and the crab-inspired gait for a specific hexapod to move forward and move backward;turn left and turn right and integrates the two gaits to apply them under different conditions.The hexapod has three servos on each legs,thus the freedom level of each leg is three-degree.From the comparative experiment,this two gait patterns are suitable for different turning demands.
文摘Small inspection robots allow for the optimal exploration of environments and the collection of data from challenging areas,particularly where there may be small access points or tight and fragile surroundings.These robots can be custom-built for specific tasks,but the design and assembly process for this can be costly,both in resources and assembly time.The use of 3D printing to create Non-Assembly mechanisms can assist in saving time and resources by reducing the number of different components required and removing the necessity for complex assembly tasks.By iterating on previous work performed in the institute,this paper introduces a novel robot design to push the capabilities of Non-Assembly systems.By building on previous knowledge,this new walking robot improves on the previous iteration by creating a more robust and reliable system,more capable of effectively exploring challenging environments accurately,while still using practices designed to save on cost and production time.Benchmark tests were performed to provide an accurate comparison against the previous design and highlight the robots marked improvements in positional accuracy over its predecessor.
