Mechanix

About

Introductory engineering courses within large universities often have annual enrolments exceeding several hundreds of students, while MOOCS and online classes have even larger classes. It is very challenging to achieve differentiated instruction in classrooms with class sizes and student diversity of such great magnitude. In such classes, professors can only assess whether students have mastered a concept by using multiple-choice questions. However, in a multiple choice scenario, students only have to identify the answer rather than create the answer, and the feedback received is only of a binary nature (right or wrong). Additionally, a growing concern among engineering educators is that students are losing both the critical skill of sketched diagrams and the ability to take a real system and reduce it to an accurate but simplified free-body diagram (FBD).

Mechanix is a sketch-based deployed tutoring system for engineering students enrolled in statics courses. Mechanix not only allows students to hand-draw solutions with planar truss and free body diagrams, just as they would with pencil and paper, but it also checks the student’s work against a hand-drawn answer entered by the instructor. It uses sketch recognition to determine both the component shapes and features of the sketched diagram and the relationships between those shapes and features. Mechanix then uses those relationships to determine whether a student’s work is correct and why it is incorrect, enabling Mechanix to return immediate personalized feedback to the student otherwise not possible in large classes. Additionally, because sketching is the preferred mode of problem solving for many professional engineers, producing a tool that utilizes sketching should increase the transfer of skills from the classroom to the real world. Finally, the iterative correction process facilitates student learning. Preliminary results suggest that Mechanix increases homework motivation in struggling students, and have shown that Mechanix is as effective as paper-and-pencil-based homework for teaching method of joints truss analysis. Focus groups have revealed that students believe Mechanix enhances their learning and that they are highly engaged while using it.

Currently, Mechanix can correct three different types of static homework problems: 1) Standard truss problems requiring calculations of method of joints, 2) Free-form free body diagrams, and 3) Creative Design problems. In creative design mode, the student must think creatively to create a viable truss that abides by the constraints. Creative design mode offers an infinite number of possible solutions for the student, and thus presents an interesting recognition problem. Additionally Mechanix contains three different interfaces: 1) the student interface, where the student answers the problem, 2) the instructor question creation interface, where the instructor enters the problem, and 3) the instructor review mode, where the instructor reviews the existing solutions (Figure 5 shows a mockup). To add questions, the instructor simply types the question, uploads an image, draws the answer, and types in the numerical answers. The drawn answer is then compared to the student’s answer for correction. Because the student needs to know where he or she is wrong, Mechanix performs sophisticated analysis on the student’s solution in an attempt to determine where the student has gone wrong. In the case of creative design mode, no solution is drawn, instead only constraints are specified, and Mechanix then uses these constraints to grade the student’s solution. Two types of feedback are given, that of a simple dropdown box, and that of a complete checklist for them to follow. We provide two types of feedback so that the instructor can provide more feedback on initial problems and less later, scaffolding the feedback.

Instructor Mode

Student Mode

General Recognition

Truss Recognition

Answer Checking

Use Mechanix in YOUR Classroom

Resources and links