Development of Active Controlled Pendulum type Bed for Ambulance

本研究的目的是为了减轻躺在救护车床上的病人的疼痛。为了实现这一目的，提出了一种主动控制摆式床身。这种床位系统可以防止病人在急救车转弯时在床上摇晃，也不会在急救车加速或减速时翻腾。该系统通过引入摆动机构来提供被动安全，并在有限的动力源下控制床面。此外，床的旋转中心与患者的重心一致，以防止患者晕车，并提供控制器的健壮性。利用最优控制理论设计了摆动床的LQ控制系统。制作了主动控制摆式床身的半比例模型，并将其加载到皮卡上。进行了数值模拟和控制实验，验证了床身系统的有效性。结果表明，平行于床面的加速度不到影响车辆加速度的20%。通过将运行中的LQ控制切换到LQI控制来抑制稳态偏差，然后构造前馈系统抑制影响车辆快速变化的加速度中与床面平行的剩余加速度。该系统根据方向盘的转角和车速估计横向加速度，根据刹车踏板的压制力估计纵向减速。通过控制实验，验证了前馈主动控制摆式床身的有效性。结果，加速度不到一半。

Purpose of this study is to reduce the pain on a patient laid in the bed of ambulance. An active controlled pendulum type bed is being proposed in order to achieve this purpose. This bed system prevents the patient from swaying on the bed as the ambulance turns around a corner and from surging as the ambulance increases or decreases the speed. The system is designed introducing the pendulum mechanism to provide the passive safety and to control the bed plane in limited power source. Also, the center of rotation of the bed is made to agree with the patient center of gravity to prevent the patient from getting carsick and to provide the robustness of the controller. A LQ control system tilting the bed is developed using the optimal control theory. A half scale model of the active controlled pendulum type bed is produced and loaded on a pickup truck. The numerical simulations and the control experiments have been conducted to confirm the effectiveness of the bed system. As the results, the acceleration parallel to the bed plane is less than 20% of the acceleration affecting the vehicle. And the steady-state deviation is suppressed by switching to the LQI control in the stoppage from the LQ control in the running.Then, a feedforward system is constructed to suppress the remaining acceleration parallel to the bed plane in the acceleration affecting the vehicle changing rapidly. The system estimates the transverse acceleration from the rotation angle of the steering wheel and the vehicle speed, and the longitudinal deceleration from the depressing force of the brake pedal. The control experiments have been conducted to confirm the effectiveness of the active controlled pendulum type bed with the feedforward system. As the result, the acceleration is less than the half.