Walking assistance can be realized by active and passive robotic walkers when their users walk on even roads.However,fast signal processing and real-time control are necessary for active robotic walkers when the users...Walking assistance can be realized by active and passive robotic walkers when their users walk on even roads.However,fast signal processing and real-time control are necessary for active robotic walkers when the users walk on slopes,while assistive forces cannot be provided by passive robotic walkers when the users walk uphill.A robotic walker with an active-passive hybrid actuator(APHA)was developed in this study.The APHA,which consists of a rotary magnetorheological(MR)brake and a DC motor,can provide mobility assistance to users walking both uphill and downhill via the cooperative operation of the MR brake and DC motor.The rotary MR brake was designed with a T-shaped configuration,and the system was optimized to minimize the brake volume.Prototypes of the APHA and robotic walker were constructed.A control algorithm for the robotic walker was developed based on the characteristics of the APHA and the structure of the robotic walker.The mechanical properties of the APHA were characterized,and experiments were conducted to evaluate the mobility assistance supplied by the robotic walker on different roads.The results show that the APHA can meet the requirements of the robotic walker,and suitable assistive forces can be provided by the robotic walker,which has a simple mechanical structure and control method.展开更多
The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive(e.g. in the case of depot operations) or highly inefficient(e.g. in indust...The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive(e.g. in the case of depot operations) or highly inefficient(e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for lowspeed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.U1813222)Hebei Provincial Natural Science Foundation of China(Grant No.E2018202316).
文摘Walking assistance can be realized by active and passive robotic walkers when their users walk on even roads.However,fast signal processing and real-time control are necessary for active robotic walkers when the users walk on slopes,while assistive forces cannot be provided by passive robotic walkers when the users walk uphill.A robotic walker with an active-passive hybrid actuator(APHA)was developed in this study.The APHA,which consists of a rotary magnetorheological(MR)brake and a DC motor,can provide mobility assistance to users walking both uphill and downhill via the cooperative operation of the MR brake and DC motor.The rotary MR brake was designed with a T-shaped configuration,and the system was optimized to minimize the brake volume.Prototypes of the APHA and robotic walker were constructed.A control algorithm for the robotic walker was developed based on the characteristics of the APHA and the structure of the robotic walker.The mechanical properties of the APHA were characterized,and experiments were conducted to evaluate the mobility assistance supplied by the robotic walker on different roads.The results show that the APHA can meet the requirements of the robotic walker,and suitable assistive forces can be provided by the robotic walker,which has a simple mechanical structure and control method.
基金funding of the SAMIRA project by the European Regional Development Fund under grant number 0801689
文摘The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive(e.g. in the case of depot operations) or highly inefficient(e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for lowspeed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.
