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Precision reducer is one of the key parts of an industrial robot, which generally incorporates two-stage cycloidal planetary drive. The theoretical engagement of cycloidal wheel and pin is a gapless engagement, but in practice, there is a gap between the cycloidal wheel and the pins due to manufacturing errors. Most of the previous research on the gap only involves the impact on the transmission accuracy,...
In the paper a new control algorithm for mobile manipulators with skid-steering platform, moving on unknown terrain, has been introduced. Due to under-actuation of such mobile platforms, the concept of factitious force (which does not exist in reality and is assumed to be always 0) has been utilised. Presented control law, in non-adaptive and adaptive version, guarantees asymptotically fast convergence...
This study will calculate and simulate the energy recovered during braking or deceleration of the traditional vehicle (KERU: Kinetic Energy Recovery Unit). Using PID controllers to control the simulation model base on driving cycles such as FTP75, NEDC, EUDC and ECE-R15. Simulation results in Matlab Simulink shown that the energy recovered can reach 4.8 kW.h depending on the velocity at the beginning...
This paper aims to analyze the safety of overactuated electric vehicle through variable curvature curve. By combined with previous general curve accident statistics, three kinds speed control targets can be presented, which is anti-skid, anti-roll and a longitudinal safety distance, to complete vehicle longitudinal dynamics control. Last, combining with the lane keeping system, fitting expectation...
In the development process of automotive chassis control system, it is difficult to estimate road parameters accurately. Based on vehicle force analysis and Dugoff tire model, the method of road friction coefficient estimation using BP neural network is proposed based on the motion states in the vehicle running process. Finally, the simulation of road friction coefficient estimation method is carried...
The four-wheel-independent-drive electric vehicle has potential superiority in improving operational efficiency and enhancing vehicle motion control performance by allocating different torques to four wheels. To achieve the energy optimization and to ensure the driving stability, a multi-objective optimal control allocation law is proposed, which composed of two steps of optimization. A pre-allocation...
In order to save energy and improve the driving distance of electric vehicle, a regenerative braking control strategy based on fuzzy control for the electric vehicle with four in-wheel motors is proposed in this paper. Firstly, the braking force is distributed between front axis and rear axis to ensure the safety and stability of the vehicle. Secondly, the braking force is distributed between hydraulic...
This paper introduces a path planning algorithm that takes into consideration different locomotion modes in a wheeled reconfigurable rover. Power consumption and traction are estimated by means of simplified dynamics models for each locomotion mode. In particular, wheel-walking and normal-driving are modeled for a planetary rover prototype. These models are then used to define the cost function of...
A reference vehicle model is proposed for ESC system, which is used for estimating if the vehicle is in stable conditions. The proposed model is a 2-DOFs nonlinear model that contains the lateral motion and rotational motion around vertical axis. When ESC system works, the lateral acceleration is often above 0.4g and the nonlinearity of vehicle can't be ignored. Therefore the nonlinear relationship...
The vehicle using omnidirectional wheels has ability to move in all directions without changing the body direction unlike a normal four wheel drive vehicle. However most of omnidirectional vehicle are designed for using only on flat ground. In this paper, we propose a new type of omnidirectional wheel, “Spiral Mecanum Wheel”, which enables vehicle climb the step. This new wheel consists of spiral...
In this study, we propose a low-cost power-assisted cart that distributes the torque of a motor using a differential gear and brakes. Carts are designed to help transport heavy payloads and have multiple applications. As the cart size and payload weight increase, cart operation becomes difficult. This led to the development of power-assisted carts, which employ actuators to support the workload.
Locomotives are equipped with slip controllers to limit a value of a wheel slip velocity and conducive to reach required locomotive tractive effort. The slip control methods are developed for tenths years, and the methods are based on several principles. Progressive methods determine an adhesion-slip characteristic slope. This method requires knowledge of an adhesion coefficient value or an adhesion...
The linear quarter-car model offers a fast and simple representation for active and semi-active suspension control design. However, this kind of model is independent of geometric characteristics, which have a significant effect on the dynamic behavior of the suspension. This paper proposes considering the geometry of the widely used McPherson suspension to compute equivalent parameters for a quarter-car...
Systematic analysis of lateral dynamics of a ground vehicle (e.g. passenger car) is presented in this paper. The results are based on the simplest possible single-track model. Effects of variations in the physical parameters — mass, the moment of inertia, tire priorities, vehicle geometry — on the response times, damping ratios, natural frequencies and other dynamical characteristics are presented...
This paper proposes an omni-directional mobile base utilizing spherical robots as its wheels. In particular, the mobile base can move in an omni-directional manner by controlling translational and rotational motion of the spherical robots. However, in practice, unnecessary rotation of the spherical robots may occur due to the presence of friction and individually controlled wheel's-direction. To overcome...
In this paper, we develop a zero-moment-point and friction force calculation framework for wheeled mobile robots on uneven terrain to evaluate roll-over and slippage tendency of the given trajectory. The proposed framework using dynamic constraints and passive decomposition has advantages of low computations and implementation cost. Simulation results using CarSim is provided to analyze the performance...
Legged robots can explore unstructured environments more effectively than wheeled robots, but high turning rate tracking is still a challenging problem, particularly on varying surfaces. Previous steering methods with small robots have shown high turn rates, but usually only on a limited set of surfaces. This paper proposes a new method for steering a miniaturized legged robot by cooperation between...
Most of the previous lane keeping algorithms are designed for the vehicle lateral control without considering the longitudinal dynamic characteristic. In this paper a new controller for combining lane keeping and speed tracking of four wheels steering and four wheels drive electric vehicle is presented. Firstly, the nonlinear system model is constructed considering the vehicle longitudinal and lateral...
A rocket-propelled miniature robot is capable to explore sites that planetary rovers cannot reach with efficiency in locomotion distance per mass. The technical difficulty is the significant variance in its flight distance because of two factors: sensitivity of error in the center of gravity with respect to the thrust axis, and solid rocket engines deviance in thrusting force. To overcome the issue,...
Generic control of wheel-on-leg robots on arbitrary uneven terrains is a challenging task due to the complexity of the robot dynamics, surface interactions, and environmental structures. This paper deals with the control of a wheel-on-leg robot with passive and active internal compliance that enables estimation of wheel-ground interaction forces. The proposed method is based on a continuous state...
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