Actively-controlled Beds for Ambulances

During transportation by ambulance, a patient is exposed to inertial acceleration when an ambulance decelerates or turns a corner. Such acceleration often gives a patient physical stress such as blood pressure variation or body sway, which causes strong pain, feeling of discomfort or sometimes critical damage for seriously injured persons. To reduce this undesirable effect of the acceleration, the authors developed the actively-controlled bed （ACB） which controls the posture of a stretcher in real time to reduce foot-to-head and lateral acceleration acting on a supine person. This paper describes development of the ACB, including control system design and performance evaluation. The control system is designed by Zakian＇s framework, which comprises the principle of matching and the method of inequalities, so that the design specifications on the tracking error and the motor torque are satisfied. From the results of driving experiments and simulation, it is estimated that the ACB can reduce the acceleration acting on a patient by 65% in the foot-to-head direction and by 75% in the lateral direction.

INDIRECT ACCELERATED ADAPTIVE FUZZY CONTROLLER

According to a type of normal nonlinear system, an indirect adaptive fuzzy （IAF） controller has been applied to those systems where no accurate mathematical models of the systems under control are available. To satisfy with system performance, an indirect accelerated adaptive fuzzy （IAAF） controller is proposed, and its general form is presented. The general form IAAF controller ensures necessary control criteria and system＇s global stability using Lyapunov Theorem. It has been proved that the close-loop system error converges to a small neighborhood of equilibrium point. The optimal IAAF controller is derived to guarantee the process＇s shortest settling time. Simulation results indicate the IAAF controller make the system more stable, accurate, and fast.

STUDY ON SENSOR-BASED CONTROL METHOD FOR HARMONIC DRIVE SYSTEM

A new type of robust traje ctory tracking control for harmonic using joint torque sensor and joint acceleration sensor information is concerned with.Joint torque sensor information is used to compensate the uncertainty of link and load parameters. Joint acceleration feedback control will enhace the robustness of the driving system, resist the dynamic uncertainties and disturbing torque acted on the joint axis within definite bandwidth, improve the joint tracking performance, and resist the vibration of the load side of the harmonic drive system. Experimental studies are carried out and comparison of several controllers , such as PD and sensor- based control, the experimental results clearly illustrate the effectiveness of the proposed methods.

An extrapolation approach for aeroengine's transient control law design

Transient control law ensures that the aeroengine transits to the command operating state rapidly and reliably. Most of the existing approaches for transient control law design have complicated principle and arithmetic. As a result, those approaches are not convenient for application. This paper proposes an extrapolation approach based on the set-point parameters to construct the transient control law, which has a good practicability. In this approach, the transient main fuel control law for acceleration and deceleration process is designed based on the main fuel flow on steady operating state. In order to analyze the designing feature of the extrapolation approach, the simulation results of several different transient control laws designed by the same approach are compared together. The analysis indicates that the aeroengine has a good performance in the transient process and the designing feature of the extrapolation approach conforms to the elements of the turbofan aeroengine.

A study on optimal control of the aero-propulsion system acceleration process under the supersonic state

In order to solve the aero-propulsion system acceleration optimal problem,the necessity of inlet control is discussed,and a fully new aero-propulsion system acceleration process control design including the inlet,engine,and nozzle is proposed in this paper.In the proposed propulsion system control scheme,the inlet,engine,and nozzle are simultaneously adjusted through the FSQP method.In order to implement the control scheme design,an aero-propulsion system componentlevel model is built to simulate the inlet working performance and the matching problems between the inlet and engine.Meanwhile,a stabilizing inlet control scheme is designed to solve the inlet control problems.In optimal control of the aero-propulsion system acceleration process,the inlet is an emphasized control unit in the optimal acceleration control system.Two inlet control patterns are discussed in the simulation.The simulation results prove that by taking the inlet ramp angle as an active control variable instead of being modulated passively,acceleration performance could be obviously enhanced.Acceleration objectives could be obtained with a faster acceleration time by5%.

The accelerator control system of CSNS

The China Spallation Neutron Source is an accelerator-based user facility for neutron,proton,muon applications and so on.The designed proton beam power is 100 kW for the first phase.Overall,the scope of accelerator control system covers four parts,the global systems,the device layer local controls and remote controls,the high-level applications and services and the integration of conventional facilities.The principle guideline is to adopt as many as possible matured technologies and commercial products in the design and implementation.The control system is based on Experimental Physics and Industrial Control System.VME64x bus is chosen for timing system and fast protection system.PLCs and embedded industrial computers are used in the device layer slow controls.Control System Studio is adopted as the high-level applications.Blade server-based virtualization platform is deployed for the computer system.The accelerator control system was completed in September 2017 and then transited to routine operations.The design,implementation and operation of the accelerator control system are described in this paper.

Robust gain-scheduled missile autopilot design based on multifrequency extended state observers

This paper describes the design and implementation of a three-axis acceleration control autopilot for an asymmetric tail-controlled,skid-to-turn tactical missile.In an earlier flight test,degraded autopilot performance was attributed to multiple disturbances and uncertainties and the presence of hidden coupling terms,giving rise to a miss distance of greater than 20 m.To address these issues,the missile dynamics are decomposed into the angular rate dynamics as fast and the acceleration dynamics as slow subsystem using the singular perturbation theory to analyze a multi-time-scale property.Multifrequency extended state observers are then incorporated into the gain scheduling technique to attenuate disturbances,thus enhancing the control performance significantly.In the proposed engineering/practical design framework for missile autopilot,simple,conventional,and explicit tuning rules are provided.And the proposed control scheme can achieve input-to-state stability across the entire flight envelope under unknown but bounded disturbances.The advantages of the method over existing benchmark approaches are shown through nonlinear numerical simulations.This is supported by evidence from a new flight test result with a miss distance of only 2 m.

Research on the application of digital power supply based on domestic FPGA

Purpose The digital controller for the accelerator magnet power supply typically employs a field-programmable gate array(FPGA)as the signal processing chip for executing digital processing of closed-loop control.Currently,FPGA chips are predominantly utilized in Intel or Xilinx products.To address the“key areas and stranglehold”issue pertaining to FPGA chips in accelerator power supply,we have devised a digital power supply prototype using a domestic FPGA chip and validated its feasibility in the upgrade project’s magnet power supply digital transformation plan for the Beijing Electron Positron Collider(BEPCII).Method A domestic FPGA chip from the Seal5000 SA5Z-30-D1 series by Xi’an ZhiDuoJing Microelectronics Co.serves as the core component for the design of a digital corrector magnet power supply to replace the existing analog controlled corrector power supply at BEPCII.The power supply’s digital control of the closed loop is achieved through the use of a hardware description language,and the digital controller hardware is constructed based on the original power supply power topology.Results and conclusions After conducting experiments and tests on the power supply prototype,we have successfully met the current operational requirements of the BEPCII corrector power supply,thus confirming the feasibility of utilizing domestic FPGA for digital application on accelerator power supply.