Dual Robot Log Handling

The goal of the project is to design end effectors and program two 6-axis robots to pick up, rotate, and manipulate a log through a band saw to cut a log into a cant. The end effectors will bolt to the 6th axis of each robot and secure the log by penetrating the wood at each end. The cutting planes for each log will be determined by an optimized scan and communicated to the robots via a Programmable Logic controller. In the first year of the project, our goal is to complete the end effector design and program the robots to cut a single face of the cant.

=Project Value= In modern sawmills, logs are cut into lumber through a massive automated assembly line of hydraulic equipment, which is expensive to maintain and requires extensive computing power. This could be replaced by a two-robot system which can cut logs with greater efficiency and reduced overhead, maintenance, and computing costs.

=Product Requirements=

=End Effector= The biggest challenges in the end effector design is implementing shock absorption along the log longitudinal axis without compromising bending under the gravity load of the log and while remaining within the strict size requirements. We constructed a rapid prototype to test the shock absorption method of mounting compression springs around the mounting bolts. This design would require 2 plates with the springs located in between each plate. The prototype can be seen below. After fabricating the spikes and test fixture, we no longer had access to the university's load frame machine due to the outbreak of COVID-19. Since we were not able to obtain these test results, we needed a new method to select spike tip geometry and compression springs. Idaho Forest Group had pre-manufactured spikes which we decided to incorporate in our design. We found research online regarding the force required to extract a nail from wood, and we used this model for spring selection. This led us to find a list of 6 springs which could fit within the housing member, withstand the maximum expected force, and deflect approximately 0.25 - 0.5 inches. Any of these springs will be suitable for our final design, which can bee seen below.
 * Rapid Prototyping :
 * Design Solution :
 * End Effector Spike Penetration Testing :
 * End Effector Spike Geometry :
 * End Effector Design :

=PLC Programming= The PLC's role is to communicate data from an optimizer to the robots. Prior to reaching the robots, each log is scanned by an optimizer which generates unique cutting paths to maximize the economic value of each log. For each log, we need the following parameters: length, orientation, geometric center at each end, and initial and final cutting plane height. The PLC will receive these variables as each log is scanned, convert them to coincide with the robot coordinate system, and output them to the robots.

=Robot Simulation= In order to perform move each log through unique cutting planes for each log, the robots need to be able to receive the PLC data and automatically account for log geometry. This requires a baseline program which cuts one face of a perfectly cylindrical, infinitesimal log. Embedded in the program are offsets which become filled by optimizer data for each log via the PLC. With these offsets, the robots can perform the following motions to cut a log into a cant.

=Human Machine Interface=

=Design Validation=

=Team Members=

=Additional Documentation=


 * Schedule
 * Budget
 * Meeting Minutes
 * PLC Training
 * End Effector Alignment Rapid Prototype Drawing Package
 * Design Validation Plan
 * Team Contract