Rescue equipment is vital to restore and maintain the combat effectiveness of the army. Armored rescue vehicles are important equipment for troops to carry out salvage and repair tasks. The rescue capability of armored salvage vehicles directly affects the completion of rescue tasks, which is an indispensable capability of support equipment. Scientific, objective, accurate, and comprehensive evaluation of the rescue capacity of rescue vehicles helps grasp and discover defects in capability in time, provides a basis for task evaluation, and provides reference for improvement of rescue and repair systems. In this paper, AHP and a fuzzy comprehensive evaluation method are used for evaluation. Through investigation and analysis, AHP is used to determine the relative weight of each index at the same level, and then the multi-level evaluation index is determined; finally, the fuzzy comprehensive evaluation method is used for the comprehensive assessment of the rescue ability of armored vehicles. The example shows that the method can evaluate the salvage ability of the salvage vehicle objectively and accurately.

The AHP-fuzzy comprehensive evaluation model is mainly composed of two parts, the analytic hierarchy process (AHP) and fuzzy comprehensive evaluation. The fuzzy comprehensive evaluation is carried out on the basis of the analytic hierarchy process (AHP). They complement each other and improve the reliability evaluation ability, as shown in Figure 1[1-5].

Unlike the grey correlation evaluation method or grey evaluation method, the method opted can lower subjective factors in the evaluation process, the negative influence is weakened, and by comprehension of a number of opinions, the fuzzy problems attached to the method can be dealtwith. The objectivity and reliability of evaluation results can be enhanced.

3.1.1. Analysis of the Task Demand of Rescue Equipment

Towing, traction, operation, maintenance, and local transport capacity are elements of integrated support ability. The rescue ability mainly refers to the ability of towing and pulling back. To evaluate the capability of rescue equipment, we should comprehensively consider the tasks and capabilities of rescue equipment and then set up an evaluation index system.

Next, we analyse the support tasks of rescue equipment in offensive and defensive combat.

(a) The task of rescuing equipment in an offensive battle

$\cdot$ In the course of marching: set up points along the way, carry out rescue by radiation type, and implement rescue support.

$\cdot$ In the assembling area: carry out rescue and rush repairs and replenish equipment and oil.

$\cdot$ When we start to expand: set up the radiation support, follow up with the support, and open up the road when necessary.

$\cdot$ In deep fighting: search for damaged equipment, collect technical information, rescue silt equipment, send equipment to a safe area when needed, drag damaged equipment away from the enemy's direct fire strike range, assist in repair, and use the methods of towing or engineering operations to keep the road unblocked.

$\cdot$ When pursuing the enemy: pursue the enemy with the troops, repair damaged equipment, and collect the damaged equipment.

$\cdot$ When fighting is over: assist in cleaning up the battlefield, replenish oil and equipment, and ensure troops withdraw or enter new configuration areas.

(b) The task of rescuing equipment in a defensive battle

$\cdot$ Resist enemy fire sudden attack: strengthen self-protection and assist in on-site repair.

$\cdot$ Alert positions: assist in site repair, assist supplementary equipment and ammunition when necessary, ensure the evacuation of the police corps, and drag and carry out repair damage equipment with remedial value.

$\cdot$ In the position of fighting in the position: collect war damage information, receive battlefield rescue instructions, take charge of rescue, tow and transport equipment and ammunition within the position, assist repair forces to carry out site repair, and take part in the construction of temporary work when necessary.

$\cdot$ When carrying out the counter attack: implement collateral protection and collect damage equipment.

$\cdot$ Retreat: protect the troops from retreat, transport valuable equipment to the rear, and participate in road damage if necessary.

$\cdot$ When we finish fighting: clean up the battlefield, replenish oil supplies and equipment, and ensure that the troops recover positions or attack.

3.1.2. Analysis of the Ability Requirement of Rescue Equipment

To accomplish these tasks, the salvage equipment should have the following abilities:

$\cdot$ High mobility: capable of marching and fighting with armored vehicles in various environments.

$\cdot$ Armored protection, camouflage measures, and, if necessary, protective measures against nuclear, chemical, and biological weapons.

$\cdot$ In addition to the arms carried by the occupants, there should also be vehicular weapons.

$\cdot$ Having the same environmental adaptability as armored vehicles.

$\cdot$ It is possible to carry out rapid rescue for damaged armored vehicles such as trenches, silting, and overturning, so as to salvage submerged armored vehicles.

$\cdot$ Fast and reliable traction for armored vehicles losing their walking ability.

$\cdot$ Appropriate field repair capacity.

$\cdot$ Minor civil work ability.

$\cdot$ Having the same or comparable communication and observation capabilities with service objects to meet the needs of wartime command and technical observation.

$\cdot$ Better self-rescue and service performance.

3.1.3. Evaluation Index System of Rescue Equipment Capability

Considering the construction, mission need, ability requirement, and other factors of rescue equipment, after two rounds of expert consultation, the first level parameter is composed of the information capacity, mobility, protection capability, towing capacity, delivering capacity, self-help ability, support ability, lifting capacity, and repair capacity[6-12].

Information capability refers to the ability to receive instructions from the superior, the ability to handle and transfer under the field conditions, and the ability of positioning and navigation in the battlefield environment. It includes two-level indexes, such as communication ability, command ability, control ability, and battlefield reconnaissance ability.

The maneuver ability refers to the matching degree of the maneuver ability required by the rescue vehicle and the requirement of the accompany support. It includes two-level indexes, such as fastmaneuver ability, mobile capacity, and flexible operation level.

Protection ability refers to the ability to protect from attacks in the battlefield and to continue to complete the support task after the attack. It includes two-level indexes, such as body protection ability, armor protection ability, smoke screen protection ability, NBC defense performance, and protective weapon performance.

The ability of dragging and saving refers to the maximum dragging ability and the ability to complete the task of dragging and saving. It includes two grades, including rated tension, maximum pull force, maximum support force, effective length of the winch wire rope, quality of accessories for dragging and rescue, and size of the auxiliary winch.

The lifting capacity refers to the rated lifting weight and the ability to complete the lifting task during the rescue process. It includes two grades of rated weight, angle range, length of telescopic arm, and so on.

The traction ability refers to the maximum limit of the salvage vehicle when it is carried out and the ability to complete the towing task during the rescue process. It includes two-level indexes, such as maximum decoupling force, maximum traction speed, average traction speed, minimum turning radius, and connection mode.

Self-rescue capability refers to the ability to rescue itself after being damaged. It includes two-level indexes, such as self-saving ability of the winch, self-rescue ability of the log, and self-rescue ability of the civil work.

The support capability refers to the ability to meet the requirements of the top support when the rescue task is carried out. It includes two grade indexes, such as efficiency of the earth pushing operation and maximum support.

The ability to rush repairs refers to the ability of emergency repair and rapid repair for damaged equipment in the battlefield. It includes two-level indexes, such as power generation capacity, charging capacity, welding ability, cutting ability, quick repair ability, and lifting ability.

According to the above discussion, the evaluation index system of rescue capability is set up as shown in Figure 1.

The establishment of an index system considered the representative and the main index, and there is a logical relationship between the indexes. This evaluation index system can cover most cases of rescue equipment utilization. If we encounter a very special environment in work, we can adjust the specific indicators according to the idea of the paper.

Because the evaluation index involves different fields, some evaluation indexes can be calculated quantitatively by using the formula, but others cannot. Therefore, this paper divides the index into two categories, quantitative and qualitative, selects the corresponding evaluation methods according to the characteristics of the single index, and finally sets up a single index evaluation model.

3.2.1. Evaluation Criteria of Quantitative Indicators - Single Index Evaluation Model

Considering that the evaluation should be implemented easily and has good applicability, we fully absorb the experience of the design and test analysis of the salvage car when we choose the quantitative index. In determining the calculation method of the quantitative index, we draw on the quantitative method of making an equipment technical index in the evaluation of equipment adaptability. When determining the scope of the index, we can select the range of quantitative indicators consistent with the rescue capacity of the rescue vehicle by consulting experts and literature. The advantage of this method is not only to ensure the reliability of rescue data, but also to establish the relationship between rescue equipment evaluation and design argumentation.

In this paper, the general semi trapezoid distribution function is used as the membership function of the index evaluation[13]. The specific methods are as follows.

For hypothetical evaluation index factor set ${{X}^{T}}=\left\{ {{x}_{1}},{{x}_{2}},\cdots ,{{x}_{m}} \right\}$ and evaluation grade standard $V=\left\{ {{v}_{1}},{{v}_{2}},\cdots ,{{v}_{n}} \right\}$, assume ${{v}_{j}}$ and ${{v}_{j+1}}$ are adjacent to the two-level standard. The single index evaluation models of quantitative indicators can be broadly classified into two categories.

(a) Maximization ${{f}_{\max }}$

For the maximization model, the larger the index, the better. When ${{v}_{j+1}}>{{v}_{j}}$ is known, the membership function of the ${{v}_{j}}$ level is as follows.

(b) Minimization${{f}_{\min }}$

For the minimization model, the smaller the index, the better. When ${{v}_{j+1}}<{{v}_{j}}$ is known, the membership function of the ${{v}_{j}}$ level is as follows.

In the actual evaluation process, different evaluation models should be selected according to different evaluation indexes.

3.2.2. Evaluation Criteria for Qualitative Indicators

For some evaluation indexes that should not be calculated by formula, we should use a qualitative analysis method to evaluate them. This paper adopts the four-level evaluation method that divides the index into four grades: excellent, good, middle, and bad. The four-level evaluation corresponds to 100-85 points, 85-70 points, 70-60 points, and 60 points below the percentage system. The four-level evaluation method, combined with the expert scoring method, can achieve quantitative analysis of qualitative indicators. Through the normalization of the evaluation results, the membership function of the qualitative index can be determined, and the qualitative and quantitative evaluation results can be unified[14].

This paper focuses on the processing method and does not introduce the scope and calculation method of the specific evaluation index in detail.

The evaluation index of the rescue capability of ambulances is a dynamic system that changes with the development of evaluation time, evaluation purpose, and equipment development level. The change of these factors will lead to the change of evaluation criteria. Therefore, we must determine the evaluation criteria from the perspective of development.

The analytic hierarchy process (AHP)[14-18] is a common method to determine the weight coefficient of the index. Through the comparison of 22 indexes, the analytic hierarchy process constructs the judgment matrix and obtains the quantitative description about the index of subjective judgment. Then, the value of the maximum characteristic of the judgment matrix λ_max, the feature vector W, and the weight vector of indexare calculated, and the validity of the index weight coefficient vector is determined by the consistency test. Part of the rescue ability evaluation index system as shown in Figure 2.

Through expert consultation, the relative importance of the ${{B}_{r}}$ layer, ${{B}_{rs}}$ layer, and ${{B}_{rst}}$ layer can be examined, and the ($B-{{B}_{r}}$) and ($B-{{B}_{rs}}$) judgment matrix can be obtained. The first level index judgment matrix is listed in Table 1.

According to the methods mentioned above, the geometric mean method is used to solve the weight vectors of indicators. According to the order, the final weight of level ${{B}_{rst}}$ indicators level ${{B}_{rs}}$ and ${{B}_{r}}$ are calculated in series, and the final result of B is listed in Table 2.

(a) To determine the qualitative indicators of evaluation

Experts were invited to mark the various qualitative indicators of the rescue ability of a tank rescue vehicle according to the evaluation criteria of qualitative indicators in order to finally obtain an evaluation set of qualitative indicators.

Taking “information capacity” as an example, if 12 experts out of 20 experts assessed “good” and four experts assessed “excellent” and “medium” each, we can get the fuzzy evaluation matrix: [0.2 0.6 0.2 0].

(b) Evaluation of quantitative indexes by membership function

The set of quantitative indicators can be evaluated by specific performance parameters. According to the specific type, the membership degree can be calculated according to the algorithm of the maximum model and the minimal model.

According to $B\text{=}A\circ R$, calculate the fuzzy operation results of different indicators at different levels. A is the weight of each subordinate factor of B, and R is the fuzzy evaluation matrix. Then, the comprehensive evaluation result can be gained. For this example, the calculation result is:

To validate the effectiveness according to the principle of maximum membership degree:

$\alpha \text{=}\frac{{{\beta }'}}{{{\gamma }'}}=\frac{p\beta -1}{2\gamma (p-1)}$

In the equation, $\beta =0.537,\text{ }\gamma =0.3826,\text{ }p=4$, so

$\alpha =\frac{p\beta -1}{2\gamma (p-1)}=\frac{4\times 0.537-1}{2\times 0.3826(4-1)}=0.6256>0.5$

Therefore, according to the principle of maximum membership degree, it is considered that the salvage ability of the tank tested is “benign”.

According to the evaluation results, the reason that the rescue ability cannot reach “excellent” is that “drag and rescue capability”, “traction ability”, “support ability”, and “lifting capacity” have failed to achieve the “excellent” requirement in the level 2 evaluation process. The basic reason is that the traction speed, steering radius, maximum supporting force, and length of the telescopic boom are unable to meet the requirement.

In this paper, the AHP fuzzy comprehensive evaluation method is applied to the rescue capability evaluation so that it is possible to quantitatively evaluate the rescue ability and perform grading. The research helps make a quick decision when choosing equipment for special tasks.

The measurement of the rescue ability of different types of rescue vehicles and repair vehicles can help with maintenance and support resource managers to quantitatively evaluate decisions when selecting rescue equipment. It is also helpful when discussing technical performance indexes and improving existing equipment by improving the pertinence and effectiveness. It also has a certain reference value for the evaluation of the comprehensive support performance of equipment.