Optimized asset maintenance and replacement schedule

• US 9,959,515 B2
• Filed: 07/10/2015
• Issued: 05/01/2018
• Est. Priority Date: 11/24/2014
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Phan, Dung, Xiong, Jinjun
• Primary Examiner(s): Yi, Roy Y
• Application Number:
  US14/796,704
• Publication Number:
  US 20160148137A1
• Time in Patent Office: 1,026 Days
• CPC Class Codes: G01M 99/008 by doing functionality tests
• CPC Class Codes: G06Q 10/06312 Adjustment or analysis of established resource schedule, e.g. resource or task levelling, or dynamic rescheduling
• CPC Class Codes: G06Q 10/20 Administration of product repair or maintenance
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

There are provided a system, a method and a computer program product for generating an optimal preventive maintenance/replacement schedule for a set of assets. The method includes receiving data regarding an asset, said data including a failure rate function of said asset, a cost of preventative maintenance (PM) of said asset, a cost of an asset failure, and a cost of replacing an asset. An optimal number K of preventative maintenance time intervals t_k and an indication of a possible replacement is computed and stored for each asset by minimizing a mean cost-rate value function with respect to an electrical age of the asset. A first PM schedule is formed without consideration of labor and budget resource constraints. The method further generates a second maintenance schedule for a system of assets by minimizing a deviation from the optimal PM time intervals subject to the labor and budget resource constraints.

Claims

1. A method for decreasing a failure rate of each asset of a set of assets comprising:

receiving, at a programmed hardware processor, data regarding an asset, said data including a failure rate function capturing a condition of said asset up to a point in time, a cost of preventative maintenance (PM) of said asset, a cost of an asset failure, and a cost of replacing an asset;

receiving, at said programmed hardware processor, a further input specifying a time horizon;

determining, at said programmed hardware processor, whether there is a need to replace said asset, and when a replacement of said asset is needed;

computing, at said programmed hardware processor, a mean cost-rate optimization problem formulated as an objective function of a total cost of the asset over said specified time horizon, said total cost being a function of a cost of preventative maintenance (PM) of said asset for K−

1 PMs, and an expected cost of repairs for an asset failure computed as a function of said failure rate function, and the cost of replacing an asset;

computing, using the programmed hardware processor, an optimal number of preventative maintenance actions K and time intervals t_k for each asset independently by minimizing said objective function with respect to an age of the electrical asset y_k, where k represents a k^th PM, wherein said schedule is formed without considering a labor and budget resource constraint; and

the programmed hardware processor device further storing said optimal number of preventative maintenance time intervals for each asset as data in a memory storage device operatively coupled with said processor device; and

the programmed hardware processor device generating a final maintenance schedule for the system of assets based on stored said optimal number of preventative maintenance time intervals by minimizing a deviation from the computed optimal PM time intervals subject to the labor and budget resource constraints.

2. The method of claim 1, wherein said optimal number of preventative maintenance time intervals includes:

a number K of PM intervals and an indication of a possible replacement; and

a time interval t_k for the k^th PM.

3. The method of claim 2, further comprising:

receiving, at said programmed hardware processor, an input specifying a time horizon;

determining, at said programmed hardware processor, by said processor device, whether there is a need to replace said asset, and with no replacement needed,

determining, at said programmed hardware processor, the optimal scheduled intervals t_k by minimizing a first mean cost-rate optimization problem formulated as a first objective function of a total cost of the asset over said specified time horizon, said total cost being a function of a cost of preventative maintenance (PM) of said asset for K−

1 PMs, and an expected cost of repairs for an asset failure computed as a function of a failure rate function.

4. The method of claim 3, wherein the first objective function of a total cost of the asset to be minimized is represented as f₁(y, K) such that:

5. The method of claim 1, wherein the objective function of a total cost of the asset to be minimized is represented as f₂(y, K) such that:

6. The method of claim 1, wherein computing a failure rate function h₀(t) of an asset comprises:

receiving, at said programmed hardware processor, parameter values comprising;

Weibull parameter input values α

, β

, a current age t₀ of the asset, a number of simulation intervals N, a time interval Δ

t for simulation, an asset aging factor acc_factor, and a given time t wherein

7. The method of claim 1, wherein said minimizing a deviation from the optimal PM time intervals subject to the labor and budget resource constraints comprises:

solving, using parallel integer linear programming at said programmed hardware processor;

8. The method of claim 7 further comprising:

comparing, at said programmed hardware processor, said impact weight w_n against a threshold; and

if the impact is bigger than said threshold;

fixing, using said programmed hardware processor, a maintenance schedule computed for the n-the asset; and

selecting, by said programmed hardware processor, values for said lower and upper bounds for PM intervals to reduce a size of integer linear programming problem.