Walking on inclined terrains or slopes is challenging for multi-legged robots. Robots should be able to handle more strict constraints imposed by the physical system than they do on flat terrains, such as smaller leg ...Walking on inclined terrains or slopes is challenging for multi-legged robots. Robots should be able to handle more strict constraints imposed by the physical system than they do on flat terrains, such as smaller leg workspace and tighter stability margin. At the same time, robots need to autonomously generate constrained and stable motions to accommodate terrain inclination and unevenness. With regard to these issues, this paper provides a solution from two perspectives, mechanism design and planning methodology. The robot mechanism with a 1-DOF waist is firstly proposed to meet the requirements of the leg workspace and the static stability. After that, a step rolling planning scheme is introduced, in which the robot schedules its body planar 2D motion according to the human guidance and plans its elevation, roll, pitch as well as leg motions autonomously incorporating sensory feedbacks. The step rolling planning scheme ensures smooth and safe motion transitions from step to step.At last, simulations and experiments are carried out, demonstrating the effectiveness of our mechanical design and the proposed planning method.展开更多
As kinematic calculations are complicated, it takes a long time and is difficult to get the desired accurate result with a single processor in real-time motion control of multi-degree-of-freedom(MDOF) systems. Another...As kinematic calculations are complicated, it takes a long time and is difficult to get the desired accurate result with a single processor in real-time motion control of multi-degree-of-freedom(MDOF) systems. Another calculation unit is needed, especially with the increase in the degree of freedom. The main central processing unit(CPU) has additional loads because of numerous motion elements which move independently from each other and their closed-loop controls. The system designed is also complicated because there are many parts and cabling. This paper presents the design and implementation of a hardware that will provide solutions to these problems. It is realized using the Very High Speed Integrated Circuit Hardware Description Language(VHDL) and field-programmable gate array(FPGA). This hardware is designed for a six-legged robot and has been working with servo motors controlled via the serial port. The hardware on FPGA calculates the required joint angles for the feet positions received from the serial port and sends the calculated angels to the servo motors via the serial port. This hardware has a co-processor for the calculation of kinematic equations and can be used together with the equipment that would reduce the electromechanical mess. It is intended to be used as a tool which will accelerate the transition from design to application for robots.展开更多
The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate ...The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate the articulated torques, which results in a large safety margin or a large number of calculations. To quickly obtain accurate articulated torques, an analysis method for the articulated torque is presented for an electrically driven heavy-duty six-legged robot. First, the rearmost leg that experiences the maximum normal contact force is confirmed when the robot transits a slope. Based on the ant-type and crab-type tripod gaits, the formulas of classical mechanics and MATLAB software are employed to theoretically analyze the relevant static torques of the joints. With the changes in the joint angles for the abductor joint, hip joint, and knee joint, variable tendency charts and extreme curves are obtained for the static articulated torques. Meanwhile, the maximum static articulated torques and the corresponding poses of the robot are also obtained. According to the poses of the robot under the maximum static articulated torques, ADAMS software is used to carry out a static simulation analysis. Based on the relevant simulation curves of the articulated torques, the maximum static articulated torques are acquired. A comparative analysis of the maximum static articulated torques shows that the theoretical calculation values are higher than the static simulation values, and the maximum error value is approximately 10%. The proposed method lays a foundation for quickly determining accurate articulated torques to develop heavy-duty six-legged robots.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U1613208)the Shanghai Science and Technology Innovation Action Plan(Grant No.16DZ1201001)
文摘Walking on inclined terrains or slopes is challenging for multi-legged robots. Robots should be able to handle more strict constraints imposed by the physical system than they do on flat terrains, such as smaller leg workspace and tighter stability margin. At the same time, robots need to autonomously generate constrained and stable motions to accommodate terrain inclination and unevenness. With regard to these issues, this paper provides a solution from two perspectives, mechanism design and planning methodology. The robot mechanism with a 1-DOF waist is firstly proposed to meet the requirements of the leg workspace and the static stability. After that, a step rolling planning scheme is introduced, in which the robot schedules its body planar 2D motion according to the human guidance and plans its elevation, roll, pitch as well as leg motions autonomously incorporating sensory feedbacks. The step rolling planning scheme ensures smooth and safe motion transitions from step to step.At last, simulations and experiments are carried out, demonstrating the effectiveness of our mechanical design and the proposed planning method.
基金Project(No.KBü-BAP-13/1-DR-011)supported by the Department of Bilimsel Arastírma Progeleri,Karabük University,Turkey
文摘As kinematic calculations are complicated, it takes a long time and is difficult to get the desired accurate result with a single processor in real-time motion control of multi-degree-of-freedom(MDOF) systems. Another calculation unit is needed, especially with the increase in the degree of freedom. The main central processing unit(CPU) has additional loads because of numerous motion elements which move independently from each other and their closed-loop controls. The system designed is also complicated because there are many parts and cabling. This paper presents the design and implementation of a hardware that will provide solutions to these problems. It is realized using the Very High Speed Integrated Circuit Hardware Description Language(VHDL) and field-programmable gate array(FPGA). This hardware is designed for a six-legged robot and has been working with servo motors controlled via the serial port. The hardware on FPGA calculates the required joint angles for the feet positions received from the serial port and sends the calculated angels to the servo motors via the serial port. This hardware has a co-processor for the calculation of kinematic equations and can be used together with the equipment that would reduce the electromechanical mess. It is intended to be used as a tool which will accelerate the transition from design to application for robots.
基金supported by National Basic Research Program of China(973 Program, Grant No. 2013CB035502)International Science and Technology Cooperation Project with Russia (Grant No. 2010DFR70270)+2 种基金National Natural Science Foundation of China (Grant No. 51275106)"111" Project (Grant No. B07018)Key Laboratory Opening Funding of Aerospace Mechanism and Control, China (Grant No. HIT. KLOF.2010057)
文摘The accuracy of an articulated torque analysis influences the comprehensive performances of heavy-duty multi-legged robots. Currently, the extremal estimation method and some complex methods are employed to calculate the articulated torques, which results in a large safety margin or a large number of calculations. To quickly obtain accurate articulated torques, an analysis method for the articulated torque is presented for an electrically driven heavy-duty six-legged robot. First, the rearmost leg that experiences the maximum normal contact force is confirmed when the robot transits a slope. Based on the ant-type and crab-type tripod gaits, the formulas of classical mechanics and MATLAB software are employed to theoretically analyze the relevant static torques of the joints. With the changes in the joint angles for the abductor joint, hip joint, and knee joint, variable tendency charts and extreme curves are obtained for the static articulated torques. Meanwhile, the maximum static articulated torques and the corresponding poses of the robot are also obtained. According to the poses of the robot under the maximum static articulated torques, ADAMS software is used to carry out a static simulation analysis. Based on the relevant simulation curves of the articulated torques, the maximum static articulated torques are acquired. A comparative analysis of the maximum static articulated torques shows that the theoretical calculation values are higher than the static simulation values, and the maximum error value is approximately 10%. The proposed method lays a foundation for quickly determining accurate articulated torques to develop heavy-duty six-legged robots.
