Lightweight Optimization Design of Unmanned Vehicle Body Structure Based on Multi-working Conditions Correlation

doi:10.12382/bgxb.2022.1301

Abstract

Abstract:

The higher requirements are put forward for the environmental adaptability of special unmanned vehicles in the future battlefield. In order to meet the requirements of multi-working conditions, high maneuverability and low-cost development of special unmanned vehicles, the truss body structure of unmanned vehicles is optimized by the idea of multi-working conditions correlation design and lightweight optimization. However, considering that there are many design variables, large design space and too many simulation times in multi-working conditions, a lightweight optimization method of body structure based on multi-working conditions correlation is proposed; In the proposed method, the strategy of reducing design variables interval is used to reduce the design space. Gaussian process surrogate model is introduced to replace the simulation analysis for realizing the rapid performance evaluation of structural design scheme, and the optimization of the scheme is realized using genetic algorithm. The experimental results show that the mass of the final optimization scheme is 14.12% lower than that of the initial scheme and 8.87% lower than that of the scheme optimized only by Gaussian process under the condition of multi-disciplinary performance simulation verification, such as stiffness, strength and mode.

Key words: unmanned vehicle, lightweight body structure, multi-working conditions correlation, design space reduction, surrogate model, design optimization

CLC Number:

TJ819

LI Zuoxuan, JIA Liangyue, HAO Jia, WANG Chao, WANG Guoxin, MING Zhenjun, YAN Yan. Lightweight Optimization Design of Unmanned Vehicle Body Structure Based on Multi-working Conditions Correlation[J]. Acta Armamentarii, 2023, 44(11): 3529-3542.

Figures/Tables 24

Fig.1 Truss body structure model of an unmanned vehicle

Table 1 Parameters of truss body structure model of unmanned vehicle and multi-working environment

车身结构、工况环境及车身材料	设计参数	取值范围
	L/mm	3620~3820
	W/mm	1300~1500
	H/mm	620~820
	T/mm	2~6
车身结构	L₁/mm	60~80
	W₁/mm	40~60
	L₂/mm	40~60
	W₂/mm	20~40
	L₃/mm	20~40
	W₃/mm	10~20
		冲击工况
		制动工况
		转弯工况
工况环境	7种不同工况类型C	弯曲工况
		扭转1轮工况
		扭转2轮工况
		射击工况
车身材料	材料编号M	碳素钢、铝合金、钛合金

Table 2 Property parameters of different materials

材料名称	质量密度/(t·mm^-3)	弹性模量/MPa	泊松比
碳素钢	7.80×10^-9	2.01×10⁵	0.26
铝合金	2.78×10^-9	0.70×10⁵	0.26
钛合金	4.50×10^-9	1.10×10⁵	0.34

Fig.2 Static load applied on body structure

Fig.3 Load application under different working conditions

Table 3 Constraints and loads in 7 different working conditions

工况类型	约束方向				载荷施加
工况类型	左侧前轮	右侧前轮	左侧后轮	右侧后轮	载荷施加
冲击工况	X,Y,Z	X,Y,Z	X,Y,Z	X,Y,Z	6g的Y轴方向全局载荷
制动工况	X,Y,Z	X,Y,Z	Y,Z	Y,Z	0.8g的X轴方向全局载荷
转弯工况	X,Y,Z	X,Y	X,Y,Z	X,Y	0.7g的Z轴方向全局载荷
弯曲工况	X,Y	X,Y	Y,Z	Y,Z	3g的Y轴方向全局载荷
扭转1轮工况	X,Y,Z	X,Y,Z	X,Y	X,Y,Z	6g的Y轴方向全局载荷
扭转2轮工况	X,Y,Z	X,Y,Z	X,Y	X,Y	3g的Y轴方向全局载荷
射击工况	X,Y,Z	X,Y,Z	X,Y,Z	X,Y,Z	3g的Y轴方向载荷外,还需要在顶端射击开口处施加30kN压力

Fig.4 Overall steps of optimization method

Fig.5 Design space dynamic reduction

Fig.6 Construction of Gaussian process surrogate model

Fig.7 Variable interval reduction method

Fig.8 Multi-condition body structure optimization based on genetic algorithm

Table 4 GA superparameters

超参数名称	取值
种群数目	500
遗传代数	500
交叉概率	0.7
变异概率	0.2
精英策略	每代保留最好的1个点

Table 5 Predicted maximum stress errors of the surrogate model

工况类型	预测误差/%			预测正确率/%
工况类型	RDS-GP	GP	ANN	RDS-GP	GP
冲击工况	5.07	5.07	$4.97_$	$98_$	98
制动工况	7.79	4.29	$4.22_$	$100_$	98
转弯工况	4.97	6.25	$4.24_$	$100_$	98
弯曲工况	$4.43_$	6.55	5.13	$100_$	98
扭转1轮工况	7.28	7.51	$5.52_$	$100_$	98
扭转2轮工况	$3.31_$	11.40	4.80	$100_$	78
射击工况	$4.67_$	11.90	5.51	$96_$	90

Table 5 Predicted maximum stress errors of the surrogate model

工况类型	预测误差/%			预测正确率/%
工况类型	RDS-GP	GP	ANN	RDS-GP	GP
冲击工况	5.07	5.07	$4.97_$	$98_$	98
制动工况	7.79	4.29	$4.22_$	$100_$	98
转弯工况	4.97	6.25	$4.24_$	$100_$	98
弯曲工况	$4.43_$	6.55	5.13	$100_$	98
扭转1轮工况	7.28	7.51	$5.52_$	$100_$	98
扭转2轮工况	$3.31_$	11.40	4.80	$100_$	78
射击工况	$4.67_$	11.90	5.51	$96_$	90

Table 6 Predicted maximum displacement errors of the surrogate model

工况类型	预测误差/%			预测正确率/%
工况类型	RDS-GP	GP	ANN	RDS-GP	GP
冲击工况	$0.63_$	0.63	6.72	$98_$	98
制动工况	0.94	$0.82_$	6.72	$100_$	92
转弯工况	0.81	$0.76_$	4.73	78	98
弯曲工况	$0.65_$	1.29	7.23	90	$100_$
扭转1轮工况	1.91	$1.27_$	5.58	90	$94_$
扭转2轮工况	$0.41_$	1.95	2.89	$100_$	96
射击工况	$0.16_$	1.99	4.66	$100_$	86

Table 6 Predicted maximum displacement errors of the surrogate model

工况类型	预测误差/%			预测正确率/%
工况类型	RDS-GP	GP	ANN	RDS-GP	GP
冲击工况	$0.63_$	0.63	6.72	$98_$	98
制动工况	0.94	$0.82_$	6.72	$100_$	92
转弯工况	0.81	$0.76_$	4.73	78	98
弯曲工况	$0.65_$	1.29	7.23	90	$100_$
扭转1轮工况	1.91	$1.27_$	5.58	90	$94_$
扭转2轮工况	$0.41_$	1.95	2.89	$100_$	96
射击工况	$0.16_$	1.99	4.66	$100_$	86

Table 7 Predicted body mass errors of the surrogate model

工况类型	预测误差/%			预测正确率/%
工况类型	RDS-GP	GP	ANN	RDS-GP	GP
冲击工况	$0_$	0	0.64	$100_$	100
制动工况	$0_$	0	0.62	$96_$	86
转弯工况	$0.01_$	0.09	1.20	$100_$	98
弯曲工况	$0.01_$	0.04	0.75	$100_$	100
扭转1轮工况	$0_$	0.01	0.88	$100_$	90
扭转2轮工况	$0_$	2.08	1.07	96	$100_$
射击工况	$0_$	0.54	1.18	96	$100_$

Table 7 Predicted body mass errors of the surrogate model

工况类型	预测误差/%			预测正确率/%
工况类型	RDS-GP	GP	ANN	RDS-GP	GP
冲击工况	$0_$	0	0.64	$100_$	100
制动工况	$0_$	0	0.62	$96_$	86
转弯工况	$0.01_$	0.09	1.20	$100_$	98
弯曲工况	$0.01_$	0.04	0.75	$100_$	100
扭转1轮工况	$0_$	0.01	0.88	$100_$	90
扭转2轮工况	$0_$	2.08	1.07	96	$100_$
射击工况	$0_$	0.54	1.18	96	$100_$

Fig.9 Changing trend of predicted errors of the surrogate model

Table 8 Comparison of different optimal body structure schemes

参数变量及优化目标		RDS-GP	GP	ANN
	L	3620.01	3620.00	3621.17
	W	1300.00	1318.95	1300.00
	H	620.00	720.00	620.01
	L₁	60.00	65.81	75.83
	W₁	51.26	50.00	52.20
参数变量	L₂	51.26	50.00	52.20
	W₂	36.69	39.28	39.98
	L₃	36.69	39.28	39.98
	W₃	15.00	14.68	19.98
	T	5.00	5.07	4.00
	M	碳素钢	碳素钢	碳素钢
优化目标	Mass	445.45	486.88	380.93

Table 9 Comparison of surrogate model prediction and simulation model evaluation

工况类型及优化目标		RDS-GP		GP		ANN
工况类型及优化目标		代理模型	仿真模型	代理模型	仿真模型	代理模型	仿真模型
冲击工况	Str	75.65	73.19	70.20	87.27	93.81	82.50
	Dis	2.28	2.26	2.00	2.39	1.92	2.51
制动工况	Str	62.84	60.02	58.04	59.84	73.47	69.59
	Dis	1.71	1.71	1.56	1.87	1.66	1.94
转弯工况	Str	62.84	59.59	60.33	59.32	71.65	69.28
	Dis	1.69	1.69	1.42	1.84	1.46	1.90
弯曲工况	Str	73.36	66.06	61.57	65.61	76.44	75.32
	Dis	2.03	2.01	1.80	2.15	2.04	2.27
扭转1轮	Str	105.83	90.63	91.22	101.24	97.81	102.84
工况	Dis	3.14	3.22	3.76	3.27	3.05	3.60
扭转2轮	Str	125.83	121.06	102.41	118.58	149.44	143.40
工况	Dis	3.92	3.93	3.89	3.90	4.01	4.81
射击工况	Str	66.76	68.44	68.67	67.75	90.39	78.45
	Dis	2.01	2.01	1.90	2.15	1.47	2.24
优化目标	Mass	445.45	445.44	486.88	485.46	380.93	379.60

Table 10 Statistical comparison of optimal schemes

参数变量及优化目标	RDS-GP		GP
参数变量及优化目标	最优方案均值	最优方案方差	最优方案均值	最优方案方差
L	3620.00	0.00	3635.61	1764.81
W	1300.00	0.00	1336.01	1135.66
H	620.00	0.00	708.92	691.78
L₁	60.00	0.00	64.53	5.13
W₁	51.32	1.10	48.76	1.29
L₂	51.32	1.10	48.76	1.29
W₂	36.77	0.13	39.29	0.14
L₃	36.77	0.13	39.29	0.14
W₃	15.85	3.93	14.01	2.53
T	5.00	0	5.14	0.07
M	碳素钢	碳素钢	碳素钢	碳素钢
Mass	446.35		489.78

Fig.10 Comparison of iteration times

Table 11 Static simulation check of truss body structure

工况类型	最大应力/MPa	最大位移/mm
冲击工况	71.78	2.25
制动工况	58.90	1.70
转弯工况	58.46	1.68
弯曲工况	64.80	2.00
扭转1轮工况	89.94	3.20
扭转2轮工况	120.66	3.91
射击工况	67.15	2.00

Fig.11 Static simulation analysis of truss body structure (46×)

Table 12 Dynamic simulation check of truss body structure

阶数	固有频率/Hz
1	37.24
2	60.29
3	61.42
4	71.13
5	81.35
6	89.39
7	91.34
8	95.58
9	99.59
10	102.99

Fig.12 Modal simulation analysis of truss body structure (20×)

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