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Force Control Compensation Method with Variable Load Stiffness and Damping of the Hydraulic Drive Unit Force Control System 被引量:10
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作者 KONG Xiangdong BA Kaixian +3 位作者 YU Bin CAO Yuan ZHU Qixin ZHAO Hualong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第3期454-464,共11页
Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit(HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force... Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit(HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this paper has positive compensation effects on the load characteristics variation, i.e., this method decreases the effects of the load characteristics variation on the force control performance and enhances the force control system robustness with the constant PID parameters, thereby, the online PID parameters tuning control method which is complex needs not be adopted. All the above research provides theoretical and experimental foundation for the force control method of the quadruped robot joints with high robustness. 展开更多
关键词 quadruped robot force control system hydraulic drive unit force control compensation method variable load stiffness and damping simulation
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A controllable resistor and its applications in pole-zero tracking frequency compensation methods for LDOs 被引量:1
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作者 王忆 何乐年 +1 位作者 宁志华 邵亚利 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2009年第9期117-123,共7页
This paper presents a controllable resistor, which is formed by a MOS-resistor working in the deep triangle region and an auxiliary circuit. The auxiliary circuit can generate the gate-source voltage which is proporti... This paper presents a controllable resistor, which is formed by a MOS-resistor working in the deep triangle region and an auxiliary circuit. The auxiliary circuit can generate the gate-source voltage which is proportional to the output current of an low dropout regulator for the MOS-resistor. Thus, the equivalent output resistance of the MOS-resistor is inversely proportional to the output current, which is a suitable feature for pole-zero tracking frequency compensation methods. By switching the type of the MOS-resistor and current direction through the auxiliary circuit, the controllable resistor can be suitable for different applications. Three pole-zero tracking frequency compensation methods based on a single Miller capacitor with hulling resistor, unit-gain compensation cell and pseudo-ESR (equivalent serial resistor of load capacitor) power stage have been realized by this controllable resistor. Their advantages and limitations are discussed and verified by simulation results. 展开更多
关键词 controllable resistor pole-zero tracking single-Miller-capacitor with nulling resistor unit gain compensation cell pseudo-ESR power stage
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An 11-bit 200 MS/s subrange SAR ADC with low-cost integrated reference buffer 被引量:1
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作者 Xiuju He Xian Gu +3 位作者 Weitao Li Hanjun Jiang Fule Li Zhihua Wang 《Journal of Semiconductors》 EI CAS CSCD 2017年第10期84-89,共6页
This paper presents an 11-bit 200MS/s subrange S AR ADC with an integrated reference buffer in 65nm CMOS.The proposed ADC employs a 3.5-bit flash ADC for coarse conversion,and a compact timing scheme at the flash/SAR ... This paper presents an 11-bit 200MS/s subrange S AR ADC with an integrated reference buffer in 65nm CMOS.The proposed ADC employs a 3.5-bit flash ADC for coarse conversion,and a compact timing scheme at the flash/SAR boundary to speed up the conversion.The flash decision is used to control charge compensating for the reference voltage to reduce its input-dependent fluctuation.Measurement results show that the fabricated ADC has achieved significant improvement by applying the reference charge compensation.In addition,the ADC achieves a maximum signal-to-noise-and-distortion ratio of 59.3dB at 200MS/s.It consumes 3.91mW from a 1.2V supply,including the reference buffer. 展开更多
关键词 subrange SAR ADC charge compensation unit(CCU) reference buffer
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