Applied Mechanics and Materials Vols. 789-790

Abstract: Through the design way of reducing dimension, a control algorithm of the parallel compound braking is put forwarded. The flow of reducing dimension is designed, the sampling which is based on the Design of Experiment (DOE) and off-line deterministic optimization are accomplished. The reducing dimension of dual-motor coordinate coefficient is designed and the prediction model of parallel compound braking is constructed, which are based on the data of deterministic optimization. The analysis of reliability shows that the algorithm has a higher reliability and the energy recovery efficiency of the vehicle regenerative braking is improved under the condition of well braking stability.

Abstract: Development of a reliable high-performance multirotor unmanned aerial vehicle (UAV) requires an accurate and practical model of the vehicle dynamics. This paper describes the process and results of the dynamic modeling of an unmanned aerial platform known as quadrotor. To model a vehicle dynamics, elementary physical and aerodynamical principles has been employed. Parameter estimations, from a UAV design have been obtained through direct and indirect measurements. In addition to standard configuration of VTOL (Vertical Take-Off and Landing) platform, the amortized landing gear, modeled as spring-damper system, has been added. The resulting model has been implemented in a simulation environment under MATLABs toolbox, SIMULINK. Some numerical results are presented to illustrate response of the open loop system to specific commands.

Abstract: In this paper, an actuation mechanism for high-speed aiming of a target is proposed. The mechanism is a 3DOF-SPS (spherical-prismatic-spherical) parallel manipulator and can be used for a missile defense system with a fast reaction time. This type of parallel mechanism has high rigidity against external disturbances and accordingly high stiffness and precision. The target aiming requires 2 degrees of freedom and this 3 DOF mechanism has one redundancy. For fast manipulation of the proposed mechanism, the redundancy can be exploited and an optimal solution can be found out of the infinite number of inverse kinematic solutions. For finding a near time-optimal solution, a cost function is formulated considering displacement of each parallel link and an optimization technique is used for solution of the inverse kinematic problem.

Abstract: In view of the specific environment of the reconnaissance UAV (Unmanned Aerial Vehicle), it is necessary to design a micro-inertial attitude measurement system. The ground-demo of the distributed micro-inertial attitude measurement system was set up. Then the attitude error measurement equation was deduced. Based on this, the Kalman filter using the “velocity and attitude” matching algorithm was designed. Through vehicle test, the experimental results show that the precisions of horizontal angle and azimuth angle are superior to 1.5′ and 2.3′ respectively by the proposed algorithm. All these characteristics show that the scheme is feasible and can provide reference for the engineering application of the distributed micro-inertial attitude measurement system.

Abstract: Servo pneumatics is a mechatronic approach that enables accurate position control of pneumatic drives with high speed. Simulation model of the servo pneumatic system with fuzzy PD controller has been created in Matlab-Simulink software using nonlinear mathematical model of the system. The influence of supply pressure and size of the cylinder on the positioning accuracy and speed has been studied. It is observed that the supply pressure is the most influencing factor in positioning accuracy and speed compared to the size parameters of the cylinders. Further a multi-response optimization of the system parameters minimize settling time, overshoot and ITAE (Integral of time-weighed absolute error) values has been carried out using Taguchi based Grey relational analysis methodology. The optimal system characteristics have been observed when supply pressure is 0.2 MPa, diameter of the cylinder is 0.05 m and length of the cylinder is 0.15 m.

Abstract: A slip controller that can move against the off-track and control excursion caused by slips while driving a motorized wheelchair is proposed. Detecting slips in a motorized wheelchair is to detect states of the motorized wheelchair and its motors in a traveling condition. For carrying it, slip ratios are calculated using a slip detection algorithm based on the information obtained from the six-axis IMU sensor and the encoders, which are connected to both left and right motors. The calculated slip ratios are used as control variables for improving the safety in a motorized wheelchair. In the experiment of the slip controller proposed in this study, slips are verified in a proposed track. Also, it is verified that the maximum slip ratio section is determined while turning left or right.

Abstract: This paper proposed semi active controller scheme for magnetorheological (MR) damper of a heavy vehicle suspension known as Ground Semi Active Damping Force Estimator (gSADE), where it was modified from Semi Active Damping Force Estimator (SADE) algorithm. A reported algorithm known as Groundhook (GRD) was developed where its aim to minimize tire road forces and hence reduce road damage. Thus, the objective of this paper is to investigate the effectiveness of the proposed gSADE algorithm compared to GRD and SADE. These algorithms are applied to a quarter heavy vehicle models and the simulation model was developed and simulated using MATLAB Simulink software. Ride test was conducted at three different speeds and three bump heights, and the simulation results of gSADE, SADE and GRD are compared and analysed. The results showed that the proposed controller is able to reduced tire force significantly compared to GRD control strategy.

Abstract: An optimal state feedback controller based on H₂ norm is proposed for attenuating the belt vibration caused by loading disturbance in a class of image transfer belt which is widely applied in multi-color printers. Based on the simplified mechanical model of the image transfer belt unit, the presented controller acts on the actuating torque generated by a direct-current motor and optimizes the defined variables related to the quality of the original image formation. Simulation results responding to a periodic loading disturbance ascertain its efficacy with comparisons of the conventional speed control. It is certified that the image transfer belt unit is successfully maintained in a satisfying condition with effective vibration attenuation under the proposed control architecture.

Abstract: This paper deals with the objective of controlling a satellite by driving a six-state discrete Kalman Filter to estimate angular rates of satellite base on control sensor noisy data. A typical satellite is assumed in a special orbit and orbital angular velocity and orbital angular acceleration are established. For completion of simulation linear dynamics model of satellites and environment disturbances model such as solar pressure and gravity gradient torque is derived as well. The simulation is progressed at discrete ten second which assumed as data updating rate from sensor. The noisy measurements are produced by sensor and these data is sent to the discrete Kalman Filter part to estimate the attitude and attitude rate. A right balance for Plant noise covariance matrix is determined and also results show that the rate estimates are appropriate for space missions.

Abstract: This paper presents an active safety device for skid control of small electric vehicles with in-wheel motors. Due to the space limitation on the driving tire, a mechanical brake system was installed rather than hydraulic brake system. For the same reason, anti-lock brake system (ABS) that is a basic skid control method cannot be installed on the driving tire. During braking on icy road or emergency braking, the tire will be locked and the vehicle is skidding. To prevent tire lock-up and vehicle from skidding, we proposed the combination of ABS and regenerative brake timing control. The hydraulic unit of ABS is installed on the non-driving tire while the in-wheel motors on the driving tire will be an actuator of ABS to control the regenerative braking force. The performance of the ABS and regenerative brake timing control on the emergency braking situation is measured by the simulation. The simulation result shows that the combination of ABS and regenerative brake timing control can prevent tire lock-up and vehicle from skidding.