New Trends in Robots Engineering with Professional Software SolidWorks

*Ciprian Dragne, Isabela Todirite, Marius Pandelea, Corina Radu Frenţ, Petru-Alexandru Cotfas, Veturia Chiroiu and Mihaiela Iliescu*

## **Abstract**

Engineering robotic systems stand for a challenging complex process, closely related to product development phases. Society's needs and requirements generate the idea for new robot products, which are sketched as an initial concept. This is the moment when the design phases start, engineers continue their work by evaluating and optimizing the mechanical parts according to many criteria: kinematics, dynamics, the strength of materials, NVH, thermal assessments, etc. Finally, there are established specifications for prototype execution, environment sustainability, enduser specifications, and recycling requirements. All these phases could be implemented into smart software. SolidWorks is such software enabling the creation of new mechanical designs automatically based on its programming tools. This chapter is focused on relevant advanced capabilities of SolidWorks software to assist engineers in achieving a new advanced level in mechanical design, that of automatically generating new or modifying existing concepts according to the requirements. By using professional software in research studies, new engineering procedures can be developed in order to automate the concept and design phases for many concurrent engineering methodologies, design optimization methods, manufacturing, documentation, or end-user specification. Case studies on the different types of robot systems used in healthcare and assisted living are presented.

**Keywords:** robots, mechatronic system, optimization, concurrent engineering, Solidworks, healthcare, assisted living

#### **1. Introduction**

In any concept of a robotic system, the start is with a vision of the product, and an idea to design. As soon as the work for it begins, the project outline and preliminary calculations to evaluate the concept are to be done. These could involve calculi for

evaluating the kinematic performance, the working space, evaluating the loads during operation, evaluating the type of materials used, calculation of components' pre-sizing after a few significant simulation cases, calculations of the product life and cost calculations [1].

After these preliminary phases, next step is that of detailed design. Building of a detailed 3D model, kinematic evaluation of the system, strength calculations for all required cases, evaluation calculations according to other criteria, steps for optimizing components that do not meet the needed requirements, durability calculations, and service life assessment of components - all of these represent bases of a complex engineering process [2].

Both preliminary and detailed calculation cases are multidisciplinary assessments. These may include both strength analysis and assessments of dynamic behavior, thermal effect, interaction with substances that require an assessment of fluid flow, etc.).

This chapter, gives an overview of some practical methods of product design, following all the aspects mentioned above, but using modern methods and a professional CAD program. The use of modern methods means the use of personal computers both for the evaluation by already set methods and for the development of new methods, which bring to a new light all the features evaluated by older methods [3].

Finally, it is to be enlightened that the use of advanced CAD programs could enable, even "extravagant" facility such as the automatic realization of components, the evaluation of many features under the perceptions of competitive engineering, and even the automatic elaboration of projects, drawings, and technical specifications of a product [4].

Concurrent engineering is a method of designing, evaluating, and developing a product, in which the various stages of its evolution are solved simultaneously, rather than iteratively. This method reduces the time of design, implementation in production, the time required to launch onto the market, etc., which leads to improved productivity and reduce costs [5, 6].

Mechanical design of mechatronic system's components, modeling and simulation for further validation are presented next, highlighting the most efficient use of design, analysis, and manufacturing tools offered to users by SOLIDWORKS.

#### **2. Current state in design**

In the early days of engineering, designers used empirical, sequential, uni-criteria methods. All those methods were executed most of them on paper, and the project files included explanations of all the required phases and calculation steps. The need for faster evaluation methods has even necessitated the advent of calculating machines. At first, computers were not programmable, the commands were executed line by line, and so were the results. With the advent of programmable computing tools, the earlier stages of product development have been completed more quickly and new methods have been developed and diversified. Thus appeared the first dedicated computing programs. In fact, the first programs were developed even for engineering purpose of calculating some parameters that required long time of information processing. One of these areas was the methodology for calculating a trajectory required for a space shuttle, taking into account all the factors that influence this trajectory [7–10].

Over time, software for complex mathematical calculations have emerged. Some of these programs are MATLAB and Mathematica. These allow to introduce command sequences to evaluate mathematical expressions.

At the beginning, most function evaluations were performed in simplified representation systems, with variations of curves only in plane. Thus appeared the first CAD programs (for the graphical representation of the components) but they showed the pieces only in 2D representation.

However, the components encountered in reality are three-dimensional. The whole visible universe unfolds in a huge 3D scene. The emergence of components representation as three-dimensional structures seems a natural step in the development of design software.

According to the main purpose, the design phases of a product can be divided into:


Each of the above phases has acquired well-known names over time, as mentioned next.


If in the beginning, CAD-CAE-CAM programs were clearly differentiated from each other, in recent years there has been a trend of unification, so software developers have begun to unite to bring out more and more high-performance engineering applications. CAD developers today seek to benefit from the performance of subassembly calculation and evaluation programs, while CAE application developers seek to benefit from the performance of CAD applications for viewing complex 3D assemblies. One of the three areas has lagged behind in recent years. This is the realm of CAM applications. It was only after the advent of CNCs that a clear connection with the above applications was achieved. The ultimate goal of any product is its physical

realization. It is obvious that the methods of physical realization can influence all the previous methods of design, going back even to the initial conception and idea phase.

The most advanced 3D geometry modeling applications today are Catia, Solidworks, Pro-Engineer, Inventor, and Ansys. There are also others, many are developed ad hoc in various universities around the world.

As mentioned above, the methods for evaluating the performance of systems were initially developed separately from the CAD part, although applications of materials strength methods have gone hand in hand with engineering from the beginning. In any kind of concept, the engineer had to have knowledge about the possible tasks that could be supported by the designed structure. A very common method used in recent years to evaluate the performance and mechanical properties of a structure is the finite element method (FEA). The most advanced professional applications in these methods are Abaqus, Ansys, Nastran, Pam-crash, Ls-Dyna, Solidworks, Comsol, Autodesk Simulation, etc. [11–16].

A special field of research derived from evaluating the performance of a system is studying its kinematics. Establishing and evaluating the performance of a system in all positions of the workspace, including the determination of displacements, speeds, and accelerations in the system, proved necessary in the study of its dynamics. In the case of systems where the components have relative movements with respect to each other (complete rotations, complex trajectories, necessary speeds and accelerations as tasks, etc.), specific applications have also appeared for the evaluation of their kinematics. Relevant ones, as best performing applications, are Adams and Solidworks.

The development of ideas and concepts, the assembly of designed components, the evaluation of performance of the whole system, the optimization of the proposed solutions, and the choice of the best manufacturing method could be achieved with the help of modern mechanical design tools. Engineers, assisted by professional CAD-CAE-CAM design applications, could be involved in the entire product development process, from concept phase to prototyping, structural strength assessment, dynamic behavior assessment, effective manufacturing by choosing execution methods of physical and final assembly, as well as completion of all product documentation including maintenance and recycling phases.

#### **3. Concept development**

Basic aspects of concept development for different robot/mechatronic systems are presented next.

#### **3.1 Concept of robot for laparoscopic surgery**

This subchapter presents the concept of a surgical robot, designed in a kinematic chain configuration with parallel components. The medical purpose is that of surgical robot usable in brachytherapy procedures.

The development of the concept from the idea to the detailed CAD model for the surgical robotic system went through the following stages:


*New Trends in Robots Engineering with Professional Software SolidWorks DOI: http://dx.doi.org/10.5772/intechopen.105979*

**Figure 1.** *Surgical robot - CAD model.*


The (up to date) model of the robot for laparoscopic surgery is presented in **Figure 1**.

### **3.2 Concept of mechatronic system for visually impaired people**

This subchapter presents the concept of a modular mechatronic system for visually impaired people. The idea of the concept came after studying the assistive devices present on the market, and the conclusion that they can be improved. This concept aims both to address the issue of assistive devices for the visually impaired and to present a virtual prototype of a modular mechatronic system for visually impaired

**Figure 2.**

people who have acquired other mild or medium deficiencies during life or even from birth. The virtual prototype is not a prototype for a conventional device, but a custom one consisting of modules that can be added as the person has adapted to the basic set and other needs have been identified. The prototype of the mechatronic system contains multiple modular systems (location, color identification, object bypass, haptic feedback - audio, and others). People with visual impairments, in addition to having to move in closed or open spaces, need to carry out daily activities which, in most cases, require the recognition of objects in the environment.

The mechatronic system is designed so that people with mild neuro-motor dysfunctions could also be helped to move, to go up and down stairs and the robotic arm to help the blind person when there is a window on the taxiway, as well as doors from open cabinets to push them.

This system is intended to help the visually impaired in difficult times for them, such as bypassing obstacles in the way. The user in the situation when will use it in open spaces will face all kinds of situations that he has to manage.

From the mechatronic point of view, the system's basic components are (see **Figure 2**):


#### **3.3 Concept of anthropomorphic walking robot foot**

Anthropomorphic walking robots are extremely complex systems whose main problem is static and dynamic stability in the unknown environment. In most cases, the fulfillment on the tasks depends on:

• mobility of mechanical structures;

*Visualy impaired mechatronic system - CAD model. (a) whole mechatronic system (b) robotic arm sub-system.*


**Figure 3** (a) shows an innovative 3D solution in terms of mechanical structure, which is generated by the SolidWorks software. The idea was to design a walking subsystem for anthropomorphic robots that provides increased mobility and energy efficiency for effectors movements. It was chosen the version with sole consisting of three segments to ensure the extra force of movement through the toes and articulated heel for increased cushioning on contact with the support surface. The building blocks, both mechanical and electronic, are mostly chosen from SolidWorks' database.

**Figure 3** (b) shows the 3D solution of the anthropomorphic robot sole with articulated heel generated by the SolidWorks software.

The dimensions and characteristics of the designed mechanical elements are component parts of the control law that guide the heel when it lands on the support surface.

The physical parameter defines the rotation of the heel for shock cushioning is as follows (Eq. (1)):

$$\mathbf{I\_p} = \mathbf{I\_e} \times \left[ \mathbf{1} + \mathbf{F(t\_i)} \times \mathbf{3} / \left( \mathbf{k\_m^2} + \mathbf{k\_g^2} \right)^{1/2} \right] \tag{1}$$

where Ip is the weighted inclination of the normal point of contact of the heel relative to the vertical position, Ie is the estimated inclination by calculation of the normal point of contact of the heel relative to the vertical position, F(ti) is the force on

**Figure 3.** *Mechatronic system for antrophomorphic robot foot. (a) General scheme (b) Sole detail.*

the support surface at the moment ti, ₰ is the damping displacement, km and kg being the rigidities of the material, the heel of the foot and support surface, respectively.

From the point of view of the motors used, we chose the brushless DC version, in order to have a fast, precise movement and a clearly superior control of the position of the robot's legs segments.

#### **3.4 Concept of mechatronic system for locomotors disabled people**

The mechatronic system's concept presented in this subchapter is aimed to help people with disabilities, people who present different forms of paralysis of the lower limbs, or simply those who are in a period of medical recovery after undergoing operations that restrict their mobility. By the system (see **Figure 4**), these people are assisted in in transferring from the wheelchair to a vehicle or in performing various household activities.

The transfer from a wheelchair to a vehicle is the operation with a high degree of difficulty, because the person's loading area is limited, the movements of the system are limited and the possibility that the system or, worse, the person, will collide with car parts (door, pillar, chassis) is high. The system can be adapted on several types of vehicles depending on the car geometry (pillar shape and dimensions), as its concept is that of adjustable clamping hinge (see **Figure 5**).

#### **Figure 4.**

**Figure 5.** *Adjustable clamping hinge.*
