The omnidirectional legged vehicle with steering-rails has a specific mechanism feature,and it can be controlled flexibly and accurately in omnidirectional motion.Currently there lacks further research in this area.In...The omnidirectional legged vehicle with steering-rails has a specific mechanism feature,and it can be controlled flexibly and accurately in omnidirectional motion.Currently there lacks further research in this area.In this paper,the mechanical characteristics of independent walking control and steering control and its kinematics principle are introduced,and a vehicle has a composite motion mode of parallel link mechanism and steering mechanism is presented.The motion direction control of the proposed vehicle is only dependant on its steering rails,so its motion is simple and effective to control.When the relative motion between the walking and steering is controlled cooperatively,the vehicle can walk perfectly.By controlling the steering rails,the vehicle can walk along arbitrary trajectory on the ground.To achieve a good result of motion control,an equivalent manipulator model needs to be built.In terms of the mechanism feature and the kinematic principle,the simplified manipulator model consists of a rail in stance phase,a rail in swing phase,and an equivalent leg.Considering the ground surface slope during walking,a parameter of inclination angle is added.Based on such a RPP manipulator model,the equations of motion are derived by means of Lagrangian dynamic approach.To verify the dynamic equations,the motion of the manipulator model is simulated based on linear and nonlinear motion planning.With the same model and motion parameters,the dynamic equations can be solved by Matlab and the calculation data can be gained.Compared with the simulation data,the result confirms the manipulator dynamic equations are correct.As a result of such special characteristics of the legged mechanism with steering rails,it has a potential broad application prospects.The derivation of dynamics equation could benefit the motion control of the mechanism.展开更多
Existing vehicle experiment systems tend to focus on the research of vehicle dynamics by conducting performance tests on every system or some parts of the vehicle so as to improve the entire performance of the vehicle...Existing vehicle experiment systems tend to focus on the research of vehicle dynamics by conducting performance tests on every system or some parts of the vehicle so as to improve the entire performance of the vehicle.Virtual technology is widely utilized in various vehicle test-beds.These test-beds are mainly used to simulate the driving training,conduct the research on drivers'behaviors,or give virtual demonstrations of the transportation environment.However,the study on the active safety of the running vehicle in the virtual environment is still insufficient.A virtual scene including roads and vehicles is developed by using the software Creator and Vega,and radars and cameras are also simulated in the scene.Based on dSPACE's rapid prototyping simulation and its single board DS1103,a simulation model including vehicle control signals is set up in MATLAB/Simulink,the model is then built into C code,and the system defined file(SDF)is downloaded to the DS1103 board through the experiment debug software ControlDesk and is kept running.Programming is made by mixing Visual C++6.0,MATLAB API and Vega API.Control signals are read out by invoking library function MLIB/MTRACE of dSPACE.All the input,output,and system state values are acquired by arithmetic and are dynamically associated with the running status of the virtual vehicle.An intelligent vehicle experiment system is thus developed by virtue of program and integration.The system has not only the demonstration function,such as general driving,cruise control,active avoiding collision,but also the function of virtual experiment.Parameters of the system can be set according to needs,and the virtual test results can be analyzed and studied and used for the comparison with the existing models.The system reflects the running of the intelligent vehicle in the virtual traffic environment,at the same time,the system is a new attempt performed on the intelligent vehicle travel research and provides also a new research method for the development of intelligent vehicles.展开更多
基金supported by National Hi-tech Research and Development Program of China(863 Program,Grant No.2007AA11Z244)
文摘The omnidirectional legged vehicle with steering-rails has a specific mechanism feature,and it can be controlled flexibly and accurately in omnidirectional motion.Currently there lacks further research in this area.In this paper,the mechanical characteristics of independent walking control and steering control and its kinematics principle are introduced,and a vehicle has a composite motion mode of parallel link mechanism and steering mechanism is presented.The motion direction control of the proposed vehicle is only dependant on its steering rails,so its motion is simple and effective to control.When the relative motion between the walking and steering is controlled cooperatively,the vehicle can walk perfectly.By controlling the steering rails,the vehicle can walk along arbitrary trajectory on the ground.To achieve a good result of motion control,an equivalent manipulator model needs to be built.In terms of the mechanism feature and the kinematic principle,the simplified manipulator model consists of a rail in stance phase,a rail in swing phase,and an equivalent leg.Considering the ground surface slope during walking,a parameter of inclination angle is added.Based on such a RPP manipulator model,the equations of motion are derived by means of Lagrangian dynamic approach.To verify the dynamic equations,the motion of the manipulator model is simulated based on linear and nonlinear motion planning.With the same model and motion parameters,the dynamic equations can be solved by Matlab and the calculation data can be gained.Compared with the simulation data,the result confirms the manipulator dynamic equations are correct.As a result of such special characteristics of the legged mechanism with steering rails,it has a potential broad application prospects.The derivation of dynamics equation could benefit the motion control of the mechanism.
基金supported by Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20070006011)
文摘Existing vehicle experiment systems tend to focus on the research of vehicle dynamics by conducting performance tests on every system or some parts of the vehicle so as to improve the entire performance of the vehicle.Virtual technology is widely utilized in various vehicle test-beds.These test-beds are mainly used to simulate the driving training,conduct the research on drivers'behaviors,or give virtual demonstrations of the transportation environment.However,the study on the active safety of the running vehicle in the virtual environment is still insufficient.A virtual scene including roads and vehicles is developed by using the software Creator and Vega,and radars and cameras are also simulated in the scene.Based on dSPACE's rapid prototyping simulation and its single board DS1103,a simulation model including vehicle control signals is set up in MATLAB/Simulink,the model is then built into C code,and the system defined file(SDF)is downloaded to the DS1103 board through the experiment debug software ControlDesk and is kept running.Programming is made by mixing Visual C++6.0,MATLAB API and Vega API.Control signals are read out by invoking library function MLIB/MTRACE of dSPACE.All the input,output,and system state values are acquired by arithmetic and are dynamically associated with the running status of the virtual vehicle.An intelligent vehicle experiment system is thus developed by virtue of program and integration.The system has not only the demonstration function,such as general driving,cruise control,active avoiding collision,but also the function of virtual experiment.Parameters of the system can be set according to needs,and the virtual test results can be analyzed and studied and used for the comparison with the existing models.The system reflects the running of the intelligent vehicle in the virtual traffic environment,at the same time,the system is a new attempt performed on the intelligent vehicle travel research and provides also a new research method for the development of intelligent vehicles.
