Taichi Shiiba

A NEW HYBRID SUSPENSION SYSTEM WITH ACTIVE CONTROL AND ENERGY REGENERATION

SUMMARY This paper proposes new control concept of suspension, i.e. a hybrid control system with active control and energy regeneration. In ordinary passive suspension system, damper converts vibration energy into heat energy by its viscosity, so that the vibration energy is dissipated. This dissipated energy is not used practically at all. On the other hand, active suspension system has great performance of vibration isolation but it consumes extra energy. This paper presents a method to solve these problems in active imd passive control systems as follows: In passive suspension an energy regenerative damper system which converts vibration energy into useful energy is proposed. The hybrid system combines this energy regenerative system and active control in order to achieve good performance of vibration reduction with few energy consumption. By numerical simulations and basic experiments it was found that the proposed hybrid control system had satisfactory performance in both vibration reduction and ener...

Realization of realistic and rich facial expressions by face robot

Facial expression is the most import factor for communication in terms of non-verbal information. We have been developing face robot which can express facial expressions like human being for 10 years to realize emotional communication between human and robot. Because face skin is made by silicone rubber, durability of connector mounted on the backside of skin for pulling was issues to be solved. We find the solution and realize the receptionist system for practical use. The basic working principle is applied for the patent soon. The expected market with business model is shown in this paper.The goal of this study was to investigate communication with an intelligent machine such as a human-friendly robot in an environment where human and robot coexist. The face and its expressions are crucial for communication, so we have developed a face robot, which has a human-like face and can express facial expressions similar to a human being. We used air cylinders with pressurized air for the Mark I face robot, which was 1.5, times bigger than human face. In order to realize human face size, we then decided to use electrical shape memory alloy (SMA) actuators to produce facial expressions (Mark II). We realized the human size face robot though; SMA did not have enough durability and power for expressing facial expressions. For mark II we then selected McKibben-type pneumatic actuator to display facial expressions. In this paper we show the history of the face robot we have developed, discuss how to build the face robot by using McKibben-type pneumatic actuator, and show the basic ability for expressing facial expressions.

Toward rich facial expression by face robot

The paper investigates the communication with an intelligent machine such as a human-friendly robot in an environment where human and robot coexist. The face and its expressions are crucial for communication, so we developed a face robot which has a human-like face and can express facial expressions similar to a human being. The important factors of a face robot for communication with humans include: 1) it should be small and compact, and 2) it should be easy to control. Initially, we used air cylinders with pressurized air for the Mark I face robot which was 1.5 times bigger than a human face. We then decided to use electrical shape memory alloy (SMA) actuators to produce facial expressions (Mark II). We realised the human size face robot, but SMA did not have enough durability and power for expressing facial expressions. For Mark III we selected McKibben-type pneumatic actuator to display facial expressions. In this paper we show the development history of our face robot and discuss how to build the face robot by using the McKibben-type pneumatic actuator.

Flexible multibody simulation of automotive systems with non-modal model reduction techniques

The stiffness of the body structure of an automobile has a strong relationship with its noise, vibration, and harshness (NVH) characteristics. In this paper, the effect of the stiffness of the body structure upon ride quality is discussed with flexible multibody dynamics. In flexible multibody simulation, the local elastic deformation of the vehicle has been described traditionally with modal shape functions. Recently, linear model reduction techniques from system dynamics and mathematics came into the focus to find more sophisticated elastic shape functions. In this work, the NVH-relevant states of a racing kart are simulated, whereas the elastic shape functions are calculated with modern model reduction techniques like moment matching by projection on Krylov-subspaces, singular value decomposition-based reduction techniques, and combinations of those. The whole elastic multibody vehicle model consisting of tyres, steering, axle, etc. is considered, and an excitation with a vibration characteristics in a wide frequency range is evaluated in this paper. The accuracy and the calculation performance of those modern model reduction techniques is investigated including a comparison of the modal reduction approach.

Real-Time Multibody Analysis Environment for Driving Simulator

Driving simulator requires real-time calculation of vehicle dynamics in response to driver’s input, such as steering maneuver, and throttle and brake pedal operation. The authors had developed a driving simulator with a 91-DOF multibody vehicle model, and this driving simulator has been used for the purpose of ‘virtual proving ground’, which means a virtual handling and ride test environment of automobiles with a driving simulator. Multibody analysis results can be evaluated through body sensory information such as acceleration produced by 6-axis motion base and visual information by computer graphics. For real-time analysis with multibody vehicle model, the authors developed an original MATLAB-based multibody analysis program This paper deals with the details about the environment of real-time multibody analysis for driving simulator and its performance, and applications of virtual proving ground.Copyright

Evaluation of Tire and Suspension Characteristics With 6-DOF Motion Platform

An accurate description of the tire characteristics is very important for vehicle dynamic analysis. However, the characteristics of a tire are very complex, and it is not easy to develop the analytical model of tire force. It is also well known that the actual tire force is greatly affected by the suspension properties. The geometry of suspension arms determines the wheel alignment specifications such as toe and camber angle, and the stiffness and damping characteristics of suspension elements influences the vertical load of each wheel. In order to investigate the suspension properties upon the tire force characteristics, the authors have developed an original tire and suspension testing machine with 6-DOF motion platform. This system is equipped with a tire, a suspension system of a passenger car, a roller conveyer, and a 6-DOF motion platform. The developed system can evaluate the relationship between the suspension system and the tire, whereas the conventional tire testing machine measures the individual characteristics of a tire. In this paper, we report some test results with developed testing system. First, the lateral force characteristics of a tire in steady-state cornering condition were evaluated with this system, and the compliance steer characteristics of a suspension caused by the lateral force were also investigated at the same time. Next, the tire force characteristics were evaluated under the varying load condition. The random vertical displacement generated by the 6-DOF motion platform was applied to the tire, and the vertical and lateral force were observed. It was shown that the developed system can realize the evaluation of tire and suspension characteristics under various conditions.Copyright

Proposal of a tyre evaluation system with driving simulator under actual driving conditions

This article proposes a tyre evaluation system by using a driving simulator with a tyre testing machine. The dynamic characteristics of the tyre are important in the vehicle dynamics, hence the combination of tyre testing machine with driving simulator is examined to create virtual proving ground proposed by the authors. By applying measurement data from the tyre testing machine in real time instead of calculations by the tyre model, it is possible to get accurate tyre characteristics on a driving simulator. The actual prototype system was made and the dynamic tyre characteristics were evaluated. The experimental results were compared with the Magic Formula model and it was found that the proposed system has several features.

Robust Handling Performance Against Weight Variation for Light Weight Vehicle

This paper addresses the suitable design parameter for a light weight vehicle to achieve the robust handling performance against the weight variation. Running simulations were conducted to evaluate the effect of the weight variation on the handling performance. The target vehicle was a 5-seater passenger car and its weight was 600 kg. A 3-DOF vehicle model was used with which the rolling motion of a vehicle body during cornering can be considered to verify the relationship between the handling performance, design parameters, and the weight variation of the vehicle. The Magic Formula tire model was used to express the non-linearity of lateral tire forces depending on the vertical tire forces, which vary with the rolling motion of the vehicle. The handling performance was evaluated with steady-state cornering simulations and pulse response simulations.© 2014 ASME

Performance Improvement in Steering Torque Simulator With Multibody Vehicle Model

The aim of this study is to improve the performance of a steering torque simulator with a multibody vehicle model. From the perspective of the calculation speed, the augmented formulation and the penalty method were investigated as the formulation of the multibody dynamic analysis. In this study, the step size of the real-time analysis was shortened by embedding matrix libraries to the multibody dynamic analysis. In addition, the friction characteristics of the steering rack of an actual vehicle was experimentally evaluated in order to enhance the reality of the developed simulator. The friction model was identified on the basis of the experimental result and was applied to the multi-body dynamic analysis. A slalom test was conducted with the developed simulator and was compared with the experiment of an actual vehicle.Copyright

Vehicle Simulations of a Racing Kart With Flexible Multibody Dynamic Analysis

This paper deals with a dynamic analysis of a racing kart considering an elastic deformation of the kart frame. As the first step of this research, an FEM kart frame model was validated by means of static and dynamic tests. In the static test, the strain on the kart frame caused by a steering operation was measured by strain gauges, and compared to the simulation result. The dynamic response of the frame was evaluated by hammering test, and the test result was compared to that of the modal analysis. Next, a flexible multibody vehicle model was developed with this FEM frame model. In this process, model reduction based on the modal analysis was applied to reduce the degree of freedom of the flexible body. Some running tests with actual racing kart were carried out to evaluate the handling characteristic, and the comparison between simulation and experiment are discussed.© 2012 ASME