基于CAN总线的某特种机器人控制系统设计与实现

针对某特种机器人运行过程中存在控制参数复杂、被控制伺服电机和辅助设备多等问题,设计一种机器人驱动控制系统。以PLC和PC为硬件的核心构架,利用C#语言编程完成了上位机软件的开发,实现对设备的集体远程控制和参数监视,同时具备完善的报警系统,使机械结构和执行机构的安全性得到保证。该系统中,PLC结合控制局域网络总线、自由口通信和普通IO实现了对执行机构的精准管控,上位机和PLC之间选用以太网进行通信。实验结果表明所开发的特种机器人控制系统实时性好、精度高、可靠性强。

井下履带式探测机器人及其运动抗扰控制研究

井下履带式探测机器人作业环境复杂,需携带多种探测或救援装备并进行爬坡越障,易导致负载扰动,具有较强非线性和不确定性,此外,用于机器人动力驱动的永磁同步电动机(PMSM)本身是多变量、强耦合的非线性系统,目前常规的基于误差的比例积分微分(PID)控制器很难满足控制需求。针对上述问题,设计了一种四摆臂井下履带式探测机器人,并进行了爬坡越障性能分析,得出了平地直行和直行爬坡2种工况下机器人PMSM的转矩和转速;对PMSM进行建模分析,速度环采用自抗扰控制器(ADRC),电流环采用比例积分(PI)控制器,设计了ADRC+PI控制方案;采用磁场定向控制(FOC)技术对PMSM进行驱动,从而提升机器人在井下作业时的响应性能和抗干扰性能。对ADRC+PI控制方案和常规PI+PI控制方案进行仿真和对比分析,得到2种工况下PMSM的转速、转矩、相电流响应曲线,结果表明:在2种工况下,采用ADRC+PI控制方案时机器人PMSM的转速和转矩响应控制更精准,具有更小的超调量和更短的调节时间,应对外部突变干扰的能力更强,能有效提升井下履带式探测机器人的爬坡越障性能和作业稳定性。

A nonlinear bottom-following controller for underactuated autonomous underwater vehicles

The bottom-following problem for underactuated autonomous underwater vehicles （AUV） was addressed by a new type of nonlinear decoupling control law. The vertical bottom-following error and pitch angle error are stabilized by means of the stem plane, and the thruster is left to stabilize the longitudinal bottom-following error and forward speed. In order to better meet the need of engineering applications, working characteristics of the actuators were sufficiently considered to design the proposed controller. Different from the traditional method, the methodology used to solve the problem is generated by AUV model without a reference orientation, and it deals explicitly with vehicle dynamics and the geometric characteristics of the desired tracking bottom curve. The estimation of systemic uncertainties and disturbances and the pitch velocity PE （persistent excitation） conditions are not required. The stability analysis is given by Lyapunov theorem. Simulation results of a full nonlinear hydrodynamic AUV model are provided to validate the effectiveness and robustness of the proposed controller.

Dynamic modelling and PFL-based trajectory tracking control for underactuated cable-driven truss-like manipulator

In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the stabilization of planar underactuated manipulators without gravity is a great challenge since the system includes a second order nonholonomic constraint and most classical control methods are not suitable for this kind of system.Furthermore,the complexity of the truss-like structure results in tremendous difficulty of computational complicacy and high nonlinearity during dynamic modelling in addition to controller design.It is paramount to solve these difficulties for UCTM's future applications.To solve the above difficulties,this paper presents a dynamic modelling method for UCTM and a trajectory tracking control method based on partial feedback linearization(PFL)that fulfills the control goal of moving UCTM from its original position to a desired position by tracking a given trajectory of the joint angles.To achieve this,a model equivalent method is proposed to make UCTM equivalent with a three-link manipulator in the sense of dynamic behavior.Then the Lagrangian equation combined with complex vector method is proposed in the dynamic modelling process of UCTM,which simplifies the derivation procedure.Based on the established dynamic model,a coordinate transformation method is proposed to transform the control force matrix into the conventional form of an underactuated system,so that the control force can be separated from the unactuated term.The PFL method in combination with the LQR control method is then proposed to realize the targets that the joint angles can track given desired trajectory.Simulation experiments are conducted to verify the correctness and effectiveness of the proposed methods.

Research on bionic quadruped robot based on hydraulic driver

A prototype of hydraulically powered quadruped robot is presented. The aim of the research is to develop a versatile robot platform which could travel fleetly in outdoor terrain with long time of en- durance and high load carrying ability. The current version is 1. lm long and 0.48m wide, and weights about 150kg. Each leg has four rotational joints driven by hydraulic cylinders and one pas- sive translational joint with spring. The torso carries the control system and the power system. A no- vel control algorithm is developed based on a Spring-Loaded Inverted Pendulum model and the prin- ciple of joint function separation. The robot can not only cross a 150mm high obstacle in static gait and trot at 2.5km/h and l km/h on the level-ground and 10°sloped-terrain respectively, but also au- tomatically keep balanced under lateral disturbance. In this paper, the mechanical structure and control systems are also discussed. Simulations and experiments are carried out to validate the design and algorithms.

Passive Velocity Field Control of a Redundant Cable-Driven Robot with Tension Limitations

This paper proposes a novel dynamic control approach for a cable-driven robot with high redundant actuation and cable tension limitations to perform tracking task while interacting with environment. In order for a cable-driven exoskeleton robot to execute the task smoothly and safely, it is necessary to consider the tracking motion performance as well as passivity when interacting with the environment under the conditions of the actuation cables＇ redundancy and the pulling limitation. With the additional consideration of the maximum limitation of the cable tension, cable-driven robot actually can only apply a certain range of feasible wrench on the external environment, which makes the task executed by robot be restricted. In order to make designed wrench be feasible and keep the desired trajectory tracking ability, we present a new control method by extending PVFC （passive velocity field control） method considering tracking stability and passivity. The approach augmented a higher dimensional virtual flywheel dynamics in a specific orthogonal complement space of the cable＇s actuation space. After the final adjustment of the designed wrench with respect to the cable＇s constraint, this method is capable of driving the cable robot to complete the trajectory tracking task and realize the passivity.

SYNCHRONIZED PATH FOLLOWING CONTROL OF MULTIPLE HOMOGENOUS UNDERACTUATED AUVS

This paper addresses the problem of synchronized path following of multiple homogenous underaetuated autonomous underwater vehicles （AUVs）. The dedicated control laws are categorized into two envelopes： One is steering individual underwater vehicle to track along predefined path, and the other is ensuring tracked paths of multiple vehicles to be synchronized, by means of decentralized speed adaption under the constraints of multi-vehicle communication topology. With these two tasks formulation, geometric path following is built on Lyapunov theory and baekstepping techniques, while injecting helmsman behavior into classic individual path following control. Synchronization of path parameters are reached by using a mixture of tools from linear algebra, graph theory and nonlinear control theory. A simple but effective control design on direct inter-vehicle speed adaption with minimized communication variables, enables the multi-AUV systems to be synchronized and stabilized into an invariant manifold, and all speeds converge to desired assignments as a byproduct. Simulation results illustrate the performance of the synchronized path following control laws proposed.