CN103707298A - Evaluation method of continuum robot spatial path tracking effect - Google Patents

Abstract

An evaluation method of continuum robot spatial path tracking effect includes: an evaluation index establishment phase and a tracking calculation phase. The evaluation index establishment phase includes: establishing path tracking performance evaluation indexes, namely maximum error, average error, response time and control precision. The tracking calculation phase includes such steps as establishing points of tail joints of snake arms, solving path coordinates of the points, establishing a path point array, tracking a path joint segment, judging whether the joint segment is a first joint segment or not, solving a distance of points of the first joint segment, solving distances from the points to a path, calculating a maximum distance, recording response time, judging whether path tracking is completed or not, determining the maximum error, determining the average error, and determining control precision. The evaluation method of continuum robot spatial path tracking effect is available for objectively describing tracking conditions and has the advantages of low time complexity and ease of software implementation.

Description

The evaluation method of a kind of continuous type robot space path tracking effect

Technical field

The invention belongs to automatic control technology field, particularly relate to the evaluation method of a kind of continuous type robot space path tracking effect.

Background technology

Continuous type robot is the Novel bionic robot of a kind of employing " without vertebra " flexible structure, there is good bending property, can be submissive and change neatly self shape, its good flexural property even can match in excellence or beauty with biologic-organs such as snake, trunk and octopus feelers.Because the profile of continuous type robot can change flexibly, therefore there is the ability that changes self shape according to the situation of Environment Obstacles thing, working space constrained environment is had to unique adaptive capacity.It has a extensive future, and can be applied to operation, crooked pipeline in fuel tanker inspection, multi-obstacle avoidance industrial environment and the investigation in the building that subsides and search and rescue, the maintenance of nuclear power station internal duct, the occasions such as diagnosis and treatment of human body diseases.

The serial machine people of continuous type robot for consisting of a plurality of joint segments, its joint segments has structural constraint, can carry out the bending in space and rotatablely move.In the very strong environment of space structure constraint, for avoiding robot touching to cause damage or potential danger, Xu Dui robot arrives the travel path of target area and plans.The serve as reasons curve in several similar continuous type joints of path forms, and meets its structural constraint, is the final carriage that continuous type robot arrives target area.When design track algorithm, for analyzing and evaluating tracking effect, evaluation method need to be proposed.And current evaluation for continuous type robotic tracking effect still lacks foundation.

Under this technical background, not yet find to be directed at present the evaluation method of continuous type robot space path tracking effect.

Summary of the invention

In order to address the above problem, the object of the present invention is to provide the evaluation method of a kind of continuous type robot space path tracking effect.

In order to achieve the above object, the evaluation method of continuous type provided by the invention robot space path tracking effect comprises and sets up the evaluation index stage and follow the tracks of calculation stages;

(1) set up the evaluation index stage

Model path trace Performance Evaluating Indexes: worst error, mean error, response time and control accuracy;

(2) follow the tracks of calculation stages

In each step of the stepping process of snake arm track path, calculate and the needed parameters of records appraisal index, after tracking completes, determine every numerical value of evaluation index.

Setting up evaluation index in the stage, described evaluation index comprises:

1.1) worst error

Worst error refers to the maximum deviation distance of continuous type machine trader in human beings arm snake shoulder joint section and respective paths section when to path trace; Owing to only solving the joint segments variable of snake arm end joint segments in track path process, all the other joint segments repeat the motion of snake arm end joint segments, therefore after the each stepping of snake arm pedestal, the ultimate range in a demand solution end joint segments and path, the maximum in these ultimate ranges is worst error; Joint, path hop count is n, and establishing ultimate range is d _maxt(t=1,2,3 ..., nw), worst error is e _max;

1.2) mean error

Mean error refers to the mean value of all ultimate ranges of snake arm end joint segments and path joint segments, is used for weighing the average deviation size in tracing process; If mean error is

$\stackrel{\‾}{e}=\frac{\underset{t=1}{\overset{\mathrm{nw}}{\mathrm{\Σ}}}{d}_{\max t}}{\mathrm{nw}}$

1.3) response time

Response time refers to and calculates the required time of snake shoulder joint segment variable at every turn, is used for weighing the rapidity of control algolithm;

1.4) control accuracy

Control accuracy has referred to the distance of snake arm distal point and path ends point after path trace; Path is by producing according to path planning algorithm after the given impact point need detecting, with the distance of path ends point be the distance with impact point; Control accuracy is the order of accuarcy that arrives impact point for weighing.

The specific operation process of described tracking calculation stages comprise in order carry out as the next stage:

Step 1, the S01 stage of setting up snake arm end joint branch: snake arm end joint segments is divided into w part;

Step 2, ask branch path coordinate { B ₀the S02 stage: solve branch at path coordinate system { B ₀in coordinate, be denoted as array U (q) (q=1,2 ..., w);

Step 3, set up path branch array { V _p,qthe S03 stage: each joint segments of path is divided equally to w part, branch form array V (p, q) (p=1,2 ..., n; Q=1,2 ..., w);

The S04 stage of step 4, a path joint segments of tracking: snake arm takes a step forward, and completes the action of track path; That is: joint segments of snake arm end joint segments track path, the inferior stepping of pedestal j (0≤j≤w);

Step 5, determine whether S05 stage of the first joint segments: whether the tracing object that judges current snake arm end joint segments is first joint segments in path, if judgment result is that "Yes", enter next step S06 stage, otherwise next step enters the S07 stage;

Step 6, ask S06 stage of the first joint segments branch distance: the branch distance while determining track path the first joint segments, after calculating respectively in array U (q), j point is to array V (1, q) in distance a little, get minimum of a value as the point on snake arm the distance to path, the maximum in these distance values is that this is to the ultimate range d in path _maxt;

Step 7, ask branch to the S07 stage of the distance in path: during track path m joint segments (1<m≤n), need to calculate each point in array U (q) and arrive array V (m-1, q) and V (m, q) in distance a little, get minimum of a value as this some the approximation to path distance, approximate think that its minimum of a value is for the distance of this point to path;

Step 8, the S08 stage of calculating maximum range value: after the each stepping of pedestal, obtain above-mentioned distance, be similar to think apart from maximum to be the ultimate range d in end joint segments and path _maxt,

The S09 stage of step 9, recording responses time: the response time refers to and calculates the required time of snake shoulder joint segment variable at every turn, is used for weighing the rapidity of computational process;

Step 10, judged whether S10 stage of path trace: judge whether current snake arm end reaches the end in path, if judgment result is that "Yes", enter next step S11 stage, otherwise next step reenters the S04 stage, continue stepping and follow the tracks of;

Step 11, determine S11 stage of worst error value: worst error is the maximum in ultimate range;

Worst error e _maxfor:

e _max=max{d _max1,d _max2,...,d _maxt}

Step 12, determine S12 stage of mean error: mean error refers to the mean value of all ultimate ranges of snake arm end joint segments and path joint segments, is used for weighing the average deviation size in tracing process; If mean error is

$\stackrel{\&OverBar;}{e}=\frac{\underset{t=1}{\overset{\mathrm{nw}}{\mathrm{\&Sigma;}}}{d}_{\max t}}{\mathrm{nw}}$

Step 13, determine S12 stage of control accuracy: control accuracy has referred to the distance of snake arm distal point and path ends point after path trace; Path is by producing according to paths planning method after the given impact point need detecting, with the distance of path ends point be the distance with impact point; Control accuracy is the order of accuarcy that arrives impact point for weighing; This flow process so far finishes.

The situation that continuous type robot path tracking effect evaluation method provided by the invention can objective description be followed the tracks of, have time complexity low, be easy to the feature that software is realized.

Accompanying drawing explanation

Fig. 1: continuous type robot architecture's schematic diagram.

Fig. 2: the evaluation method flow chart of continuous type provided by the invention robot space path tracking effect.

Fig. 3: solve ultimate range schematic diagram.

Fig. 4: the continuous type robotic tracking three coplanar path of joint segments---emulation experiment figure.

Fig. 5: the coplanar tracking error curve map of continuous type robotic tracking's three joint segments.

Fig. 6: continuous type robotic tracking's three joint segments space three-dimensional path schematic diagrames.

The specific embodiment

Below in conjunction with the drawings and specific embodiments, the evaluation method of continuous type provided by the invention robot space path tracking effect is elaborated.

As shown in Figure 1, continuous type robot is a kind of submissive, Novel bionic robot that flexibility is high, generally compliant mechanism 1, telescoping mechanism 2, control system 3 and mobile platform 4, consists of, due to the similar sinuous snake of compliant mechanism 1, referred to herein as snake arm; Snake arm is generally the serial mechanism that a plurality of construction units form, and each construction unit is called joint segments, has rotation

with two frees degree of crooked θ, be called joint segments variable.Telescoping mechanism 2 has one degree of freedom, can realize the accurate motion of one dimension, and the hoistable platform at telescoping mechanism 2 tops is called pedestal, and it is advanced basis is provided for snake arm.The core of control system 3 for controlling, realizes the trajectory path planning of snake arm, path trace control and detection signal is processed and teletransmission.

As shown in Figure 2, the evaluation method of continuous type provided by the invention robot space path tracking effect comprises and sets up the evaluation index stage and follow the tracks of calculation stages;

(1) set up the evaluation index stage

For the better effect of following the tracks of, the model path trace Performance Evaluating Indexes: worst error, mean error, response time and control accuracy evaluated;

1.1) worst error

Worst error refers to the maximum deviation distance of continuous type machine trader in human beings arm snake shoulder joint section and respective paths section when to path trace; Owing to only solving the joint segments variable of snake arm end joint segments in track path process, all the other joint segments repeat the motion of snake arm end joint segments, therefore after the each stepping of snake arm pedestal, the ultimate range in a demand solution end joint segments and path, the maximum in these ultimate ranges is worst error; Joint, path hop count is n, and establishing ultimate range is d _maxt(t=1,2,3 ..., nw), worst error is e _max;

1.2) mean error

Mean error refers to the mean value of all ultimate ranges of snake arm end joint segments and path joint segments, is used for weighing the average deviation size in tracing process; If mean error is

$\stackrel{\&OverBar;}{e}=\frac{\underset{t=1}{\overset{\mathrm{nw}}{\mathrm{\&Sigma;}}}{d}_{\max t}}{\mathrm{nw}}---\left(1\right)$

1.3) response time

Response time refers to and calculates the required time of snake shoulder joint segment variable at every turn, is used for weighing the rapidity of control algolithm;

1.4) control accuracy

Control accuracy has referred to the distance of snake arm distal point and path ends point after path trace; Path is by producing according to path planning algorithm after the given impact point need detecting, with the distance of path ends point be the distance with impact point; Control accuracy is the order of accuarcy that arrives impact point for weighing;

(2) follow the tracks of calculation stages

In each step of the stepping process of snake arm track path, calculate and the needed parameters of records appraisal index, after tracking completes, determine every numerical value of evaluation index; Its process comprised as the next stage:

Step 1, the S01 stage of setting up snake arm end joint branch: snake arm end joint segments is divided into w part;

Step 2, ask branch path coordinate { B ₀the S02 stage: solve branch at path coordinate system { B ₀in coordinate, be denoted as array U (q) (q=1,2 ..., w);

Step 3, set up path branch array { V _p,qthe S03 stage: each joint segments of path is divided equally to w part, branch form array V (p, q) (p=1,2 ..., n; Q=1,2 ..., w);

The S04 stage of step 4, a path joint segments of tracking: snake arm takes a step forward, and completes the action of track path; That is: joint segments of snake arm end joint segments track path, the inferior stepping of pedestal j (0≤j≤w);

Step 5, determine whether S05 stage of the first joint segments: whether the tracing object that judges current snake arm end joint segments is first joint segments in path, if judgment result is that "Yes", enter next step S06 stage, otherwise next step enters the S07 stage;

Step 6, ask S06 stage of the first joint segments branch distance: the branch distance while determining track path the first joint segments, after calculating respectively in array U (q), j point is to array V (1, q) in distance a little, get minimum of a value as the point on snake arm the distance to path, the maximum in these distance values is that this is to the ultimate range d in path _maxt;

Step 7, ask branch to the S07 stage of the distance in path: during track path m joint segments (1<m≤n), need to calculate each point in array U (q) and arrive array V (m-1, q) and in V (m, q) distance a little; Fig. 3 is for solving ultimate range schematic diagram, Fig. 3 (a) is each branch distance of the first joint segments to path a bit in snake arm end joint segments, get minimum of a value as this some the approximation to path distance, the distance of a branch two each branches of joint segments to path in snake arm end joint segments when Fig. 3 (b) is track path second joint section, is similar to and thinks that its minimum of a value is for the distance of this point to path;

Step 8, the S08 stage of calculating maximum range value: after the each stepping of pedestal, obtain above-mentioned distance, be similar to think apart from maximum to be the ultimate range d in end joint segments and path _maxt,

The S09 stage of step 9, recording responses time: the response time refers to and calculates the required time of snake shoulder joint segment variable at every turn, is used for weighing the rapidity of computational process;

Step 10, judged whether S10 stage of path trace: judge whether current snake arm end reaches the end in path, if judgment result is that "Yes", enter next step S11 stage, otherwise next step reenters the S04 stage, continue stepping and follow the tracks of;

Step 11, determine S11 stage of worst error value: worst error is the maximum in ultimate range;

Worst error e _maxfor:

e _max=max{d _max1,d _max2,...,d _maxt} (2)；

Step 12, determine S12 stage of mean error: mean error refers to the mean value of all ultimate ranges of snake arm end joint segments and path joint segments, is used for weighing the average deviation size in tracing process; If mean error is

$\stackrel{\&OverBar;}{e}=\frac{\underset{t=1}{\overset{\mathrm{nw}}{\mathrm{\&Sigma;}}}{d}_{\max t}}{\mathrm{nw}}---\left(3\right);$

Step 13, determine S12 stage of control accuracy: control accuracy has referred to the distance of snake arm distal point and path ends point after path trace; Path is by producing according to paths planning method after the given impact point need detecting, with the distance of path ends point be the distance with impact point; Control accuracy is the order of accuarcy that arrives impact point for weighing; This flow process so far finishes.

The operational effect of the evaluation method of continuous type provided by the invention robot space path tracking effect:

Use MATLAB to carry out emulation experiment, in experiment, provide joint segments number and each joint segments variable after path planning; Choose single joint segments length L=50cm, pedestal step value s=1cm; Table 1 is simple joint section path trace experimental data, and along with joint segments angle of bend increases, worst error and mean error increase gradually; The tracking test data in three joint segments paths when table 2 is 0 ° for the anglec of rotation, now, three joint segments are coplanar; Table 3 is three joint segments space path tracking test data, when the anglec of rotation is different, and two joint segments antarafacials.

Table 1 simple joint section path trace experiment

The coplanar path trace experiment of table 2 three joint segments

Table 3 three joint space path trace experiments

By experimental data, can be obtained, for different paths, worst error and average error criterion can show the degree of deflection path in snake arm tracing process; Response time shows the rapidity of tracking; Control accuracy shows and impact point deviation size, the degree of accuracy of tracking is described.

For verifying evaluation method effect provided by the invention, Figure 4 shows that the analogous diagram of following the tracks of the three coplanar paths of joint segments, path joint segments variable is the 6th group of data in table 2; Fig. 4 (a), Fig. 4 (b) and Fig. 4 (c) are respectively track path first and second and three joint segments, snake shoulder joint section distal point corresponding with path joint segments in tracing process approaches path, in Fig. 4 (c), the anglec of rotation of snake arm end joint segments is 180 °, Fig. 4 (d) is after having followed the tracks of, snake arm and paths merge; Figure 5 shows that and follow the tracks of the coplanar tracking error curve map of three joint segments, circle represents that snake arm is at every turn to the ultimate range d in path _maxt, straight line is mean error

; Figure 6 shows that the analogous diagram of following the tracks of three joint segments space three-dimensional paths, path joint segments variable is second group of data in table 3; Fig. 6 (a), Fig. 6 (b) and Fig. 6 (c) are respectively track path first and second and three joint segments, Fig. 6 (d) figure is for completing path trace, snake arm and paths merge, Fig. 6 (e) is the area of space that snake arm in tracing process scanned, can find out snake arm in tracing process all the time near path.

Claims (3)

1. The evaluation method of 1.Yi Zhong continuous type robot space path tracking effect, is characterized in that: it comprises sets up the evaluation index stage and follow the tracks of calculation stages;

   (1) set up the evaluation index stage

   Model path trace Performance Evaluating Indexes: worst error, mean error, response time and control accuracy;

   (2) follow the tracks of calculation stages

   In each step of the stepping process of snake arm track path, calculate and the needed parameters of records appraisal index, after tracking completes, determine every numerical value of evaluation index.
2. 2. the evaluation method of continuous type according to claim 1 robot space path tracking effect, is characterized in that: setting up evaluation index in the stage, described evaluation index comprises:

   1.1) worst error

   Worst error refers to the maximum deviation distance of continuous type machine trader in human beings arm snake shoulder joint section and respective paths section when to path trace; Owing to only solving the joint segments variable of snake arm end joint segments in track path process, all the other joint segments repeat the motion of snake arm end joint segments, therefore after the each stepping of snake arm pedestal, the ultimate range in a demand solution end joint segments and path, the maximum in these ultimate ranges is worst error; Joint, path hop count is n, and establishing ultimate range is d _maxt(t=1,2,3 ..., nw), worst error is e _max;

   1.2) mean error

   Mean error refers to the mean value of all ultimate ranges of snake arm end joint segments and path joint segments, is used for weighing the average deviation size in tracing process; If mean error is

   

   $\stackrel{\&OverBar;}{e}=\frac{\underset{t=1}{\overset{\mathrm{nw}}{\mathrm{\&Sigma;}}}{d}_{\max t}}{\mathrm{nw}}$

   1.3) response time

   Response time refers to and calculates the required time of snake shoulder joint segment variable at every turn, is used for weighing the rapidity of control algolithm;

   1.4) control accuracy

   Control accuracy has referred to the distance of snake arm distal point and path ends point after path trace; Path is by producing according to path planning algorithm after the given impact point need detecting, with the distance of path ends point be the distance with impact point; Control accuracy is the order of accuarcy that arrives impact point for weighing.
3. 3. the evaluation method of continuous type according to claim 1 robot space path tracking effect, is characterized in that: the specific operation process of described tracking calculation stages comprise carry out in order as the next stage:

   Step 1, the S01 stage of setting up snake arm end joint branch: snake arm end joint segments is divided into w part;

   Step 2, ask branch path coordinate { B ₀the S02 stage: solve branch at path coordinate system { B ₀in coordinate, be denoted as array U (q) (q=1,2 ..., w);

   Step 3, set up path branch array { V _p,qthe S03 stage: each joint segments of path is divided equally to w part, branch form array V (p, q) (p=1,2 ..., n; Q=1,2 ..., w);

   The S04 stage of step 4, a path joint segments of tracking: snake arm takes a step forward, and completes the action of track path; That is: joint segments of snake arm end joint segments track path, the inferior stepping of pedestal j (0≤j≤w);

   Step 5, determine whether S05 stage of the first joint segments: whether the tracing object that judges current snake arm end joint segments is first joint segments in path, if judgment result is that "Yes", enter next step S06 stage, otherwise next step enters the S07 stage;

   Step 6, ask S06 stage of the first joint segments branch distance: the branch distance while determining track path the first joint segments, after calculating respectively in array U (q), j point is to array V (1, q) in distance a little, get minimum of a value as the point on snake arm the distance to path, the maximum in these distance values is that this is to the ultimate range d in path _maxt;

   Step 7, ask branch to the S07 stage of the distance in path: during track path m joint segments (1<m≤n), need to calculate each point in array U (q) and arrive array V (m-1, q) and V (m, q) in distance a little, get minimum of a value as this some the approximation to path distance, approximate think that its minimum of a value is for the distance of this point to path;

   Step 8, the S08 stage of calculating maximum range value: after the each stepping of pedestal, obtain above-mentioned distance, be similar to think apart from maximum to be the ultimate range d in end joint segments and path _maxt,

   The S09 stage of step 9, recording responses time: the response time refers to and calculates the required time of snake shoulder joint segment variable at every turn, is used for weighing the rapidity of computational process;

   Step 10, judged whether S10 stage of path trace: judge whether current snake arm end reaches the end in path, if judgment result is that "Yes", enter next step S11 stage, otherwise next step reenters the S04 stage, continue stepping and follow the tracks of;

   Step 11, determine S11 stage of worst error value: worst error is the maximum in ultimate range;

   Worst error e _maxfor:

   e _max=max{d _max1,d _max2,...,d _maxt}

   Step 12, determine S12 stage of mean error: mean error refers to the mean value of all ultimate ranges of snake arm end joint segments and path joint segments, is used for weighing the average deviation size in tracing process; If mean error is

   

   $\stackrel{\&OverBar;}{e}=\frac{\underset{t=1}{\overset{\mathrm{nw}}{\mathrm{\&Sigma;}}}{d}_{\max t}}{\mathrm{nw}}$

   Step 13, determine S12 stage of control accuracy: control accuracy has referred to the distance of snake arm distal point and path ends point after path trace; Path is by producing according to paths planning method after the given impact point need detecting, with the distance of path ends point be the distance with impact point; Control accuracy is the order of accuarcy that arrives impact point for weighing; This flow process so far finishes.

Images