Technical Awards : 2021 JSAE Award The Outstanding Technical Paper Award - An Approach to Exploring Vehicle Motion to Enhance Ride Quality of PassengerFig.6 The degree of approximation of state observer (stage cost is quadratic value of lateral acceleration): There is an appropriate value for the resonance frequency of state observer.NISSAN TECHNICAL REVIEW No.88 (2022)4. Exploring ride quality factors by designing passive motion of passengersFig.7 Methodology to construct acceleration spaceFig.8 Example of vehicle motion task: Lane change as a typical transient vehicle motion scene.At this point, the effect of the approximation accuracy of the state observer in the inverse vehicle dynamics analysis is reviewed. In the lane change behavior analysis, discussed in the next section, the state observer was mounted at the vehicle body CG position, and calculations were performed such that the lateral acceleration at the vehicle CG was minimized. The calculation results are presented in Fig. 6. With regard to the stage cost function values, it is evident that there exists an appropriate value range within which the approximation accuracy can be increased by increasing the response frequency. In other words, if the response frequency is excessively high, the differential equation of the state observer stiffens the overall system to be solved. Thus, when calculating the values, it is necessary to consider the trade-off between accuracy and the accumulation of calculation errors.Using the state observer described above, it was possible to approximate the values of the acceleration and jerk (which are related to the motion perceived by passengers) and to design the evaluation function by incorporating the approximated values in the evaluation function as state variables.An important aspect in the vehicle evaluation is to maintain identity, that is, “the condition that should be kept the same when making comparisons.” The logic of this matter has been presented in previous reports.(7) When solving the functions in the inverse vehicle dynamics analysis, identity is ensured by setting the state variables and input variables for the initial and terminal motion conditions for the vehicle motion task shown in Fig. 1. Using this method, a motion design based on the evaluation functions is established.The design fl ow can be classifi ed into the following 4.1 Designing motion for ride quality evaluationHere, the method of exploring the vehicle motion to enhance the ride quality is specifi ed. In this method, it is necessary to consider how to use the inverse vehicle dynamics to derive the minimum value of the evaluation functions, which include the amount of motion perception that occurs due to the body motion of the passengers.three phases:(i) Set the travel scene to be evaluated (vehicle motion task).(ii) Set the ride quality factors in the evaluation function and calculate the optimal solution.(iii) Reproduce the optimal solution as the vehicle motion and conduct tests and evaluations.The characteristics that can be obtained as the optimal solution are the control inputs and motion of the target vehicle. Therefore, when reproducing the vehicle motion in the last phase, the control inputs are provided to the actual vehicle, or the motion is applied to the passenger using equipment that can reproduce the acceleration space (as shown in Fig. 7).In the fi rst phase, i.e., setting the travel scene for ride quality evaluation, there will be no signifi cant difference in the results of the evaluation function related to motion perception if the travel scene is the steady driving mode; however, the results may depend on the types of control inputs (such as steering only and the addition of active acceleration/deceleration using the brake/accelerator). Therefore, in this work, transient motion is utilized as the travel scene example because it is easier to obtain the difference in motion perception under this case than in the other situations (Fig. 8).Next, the design specifi cations for the vehicle motion in this example are presented in Table 4. In the vehicle motion task, a lane change scene was set, in which the following terminal conditions were returned to straight-line travel (=0): the control inputs and the track angle and yaw angle velocity, which are the state variables for plane motion on the road. Assuming passenger ride quality enhancement, the following specifi cations were set for the evaluation functions: the steering control input minimizing specifi cation V0, assuming the ride quality of the driver, and the body roll angle acceleration minimizing specifi cation R1. For comparison, specifi cation R2 was also set; R2 represents the body roll angle 74113
元のページ ../index.html#79